Drying apparatus for electrode sheets and method for drying electrode sheets 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

[0005] , ,

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

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

Background Art

[0003] A secondary battery can be charged and discharged multiple times and is used as an energy source for various electronic devices. The electrodes of a lithium secondary battery can be formed by a drying process for drying an electrode sheet, and the drying process can be performed by a drying apparatus including a drying oven.

[0004] The electrode sheet can be formed by coating an electrode slurry containing an active material on a current collector such as aluminum (Al), copper (Cu), or foil. At this time, the electrode sheet may include a coated portion where the electrode slurry is applied and an uncoated portion where the electrode slurry is not applied. In the drying process, the solvent in the electrode slurry of the coated portion evaporates by drying, and thus the electrode slurry of the coated portion contracts. The force by which the electrode slurry of the coated portion contracts in the drying process acts as stress on the current collector of the uncoated portion and can cause electrode defects such as wrinkles and cracks. Therefore, research on technologies that can improve the safety of electrodes is necessary.

Summary of the Invention

Problems to be Solved by the Invention

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

[0006] According to exemplary embodiments of the present invention for solving the above-mentioned problems, an electrode sheet drying apparatus is provided. According to some embodiments, the electrode sheet drying apparatus includes a drying oven capable of drying an electrode sheet formed by coating an electrode current collector with a slurry; a plurality of spray nozzles disposed inside 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 water to the plurality of spray nozzles; and a pump capable of moving water through the flow path, the flow path may include one or more PTC (Positive Temperature Coefficient) heaters inside.

[0007] According to an exemplary embodiment of the present invention for solving the above-mentioned problems, a method for drying an electrode sheet is provided. The method includes 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 control unit determining, based on the water temperature, the need to operate a PTC heater; when the control unit determines that it is necessary to operate the PTC heater, activating (on) the PTC heater contained within the flow path; and spraying water, whose temperature has risen via the PTC heater, onto the electrode sheet from a plurality of spray nozzles connected to the outlet 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 exemplary embodiment of the present invention provides an electrode drying apparatus that includes a plurality of spray nozzles for spraying water onto an electrode sheet, and a flow path containing a PTC heater. The PTC heater can heat the water sprayed onto the electrode sheet, thereby supplying the electrode sheet with water at a temperature above a certain level. The water sprayed onto the electrode sheet can prevent cracks and wrinkles from occurring in uncoated areas, thereby improving the stability of the electrode.

[0009] The effects that can be obtained from exemplary embodiments of the present invention are not limited to those described above, and other effects not mentioned can be clearly derived and understood by a person with ordinary skill in the art to which the exemplary embodiments of this disclosure belong, from the following description. That is, unintended effects associated with carrying out exemplary embodiments of this disclosure can also be derived by a person with ordinary skill in the art from exemplary embodiments of this disclosure. [Brief explanation of the drawing]

[0010] [Figure 1] This is a drawing showing an electrode sheet drying apparatus according to an exemplary embodiment. [Figure 2] This is a drawing showing an electrode sheet inside a drying oven according to an exemplary embodiment. [Figure 3] This is a drawing showing an electrode sheet drying apparatus according to an exemplary embodiment. [Figure 4] This is a cross-sectional perspective view showing a flow path including a PTC heater according to an exemplary embodiment. [Figure 5] A cross-sectional perspective view showing a flow path including a PTC heater according to another exemplary embodiment. [Figure 6] This drawing shows a drying apparatus for electrode sheets according to another exemplary embodiment. [Figure 7] This is a flowchart showing a method for drying an electrode sheet according to an exemplary embodiment. [Figure 8] This flowchart shows a method for drying electrode sheets according to another exemplary embodiment. [Modes for carrying out the invention]

[0011] According to exemplary embodiments of the present invention for solving the above-mentioned problems, an electrode sheet drying apparatus is provided. According to some embodiments, the electrode sheet drying apparatus includes a drying oven capable of drying an electrode sheet formed by coating an electrode current collector with a slurry; a plurality of spray nozzles disposed inside 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 water to the plurality of spray nozzles; and a pump capable of moving water through the flow path, the flow path may include one or more PTC heaters inside.

[0012] According to some embodiments, the flow path includes a plurality of PTC heaters that extend along the 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 multiple PTC heaters is in the range of 20% to 80% of the total length of the flow path.

[0014] According to some embodiments, the flow path includes a plurality of PTC heaters, which may be arranged at regular intervals along the direction of extension of the flow path.

[0015] According to some embodiments, the flow path has 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] According to some embodiments, the flow path may include a plurality of heat-conducting blades that protrude inward.

[0017] According to some embodiments, the electrode sheet drying apparatus 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 water temperature measured by the first temperature sensor.

[0018] According to some embodiments, it further includes a first temperature sensor and a second temperature sensor. The first temperature sensor measures the temperature of the water flowing into the flow path, and the second temperature sensor may be configured to measure the temperature of the water heated by the PTC heater downstream of the PTC heater.

[0019] According to some embodiments, the first temperature sensor is included in the pump, and the 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 the PTC heater.

[0021] According to some embodiments, the drying device for the electrode sheet further includes a control unit, and the control unit may determine whether to operate the PTC heater based on the water temperature 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 drying device for the electrode sheet further includes a storage tank in which the water supplied to the plurality of injection nozzles is stored, and the flow path may further include a flow rate control unit.

[0024] According to an exemplary embodiment of the present invention for solving the above problems, a method for drying an electrode sheet is provided. A step in which a pump supplies water to a flow path having an inlet and an outlet, a step in which a first temperature sensor measures the temperature of the water flowing into the inlet, a step in which a control unit determines the necessity of operating a PTC heater based on the water temperature, and when the control unit determines that it is necessary to operate the PTC heater, an on step of operating the PTC heater included inside the flow path, and a step of spraying the water whose temperature has risen through the PTC heater onto the electrode sheet from a plurality of injection nozzles connected to the outlet of the flow path. The temperature of the water sprayed from the plurality of injection nozzles may 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 operating a PTC heater, a step in which a second temperature sensor, which is included in the flow path and located downstream of the PTC heater, measures the temperature of the water, 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 may stop (turn off) the operation of the PTC heater.

[0026] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. As a premise, terms and words used herein and in the claims should not be interpreted in a manner limited to their usual or dictionary meanings, but rather in a manner consistent with the technical spirit of the present invention, based on the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

[0027] Therefore, the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the present invention; as of the time of filing, there may be a variety of equivalents and modifications that can substitute for them.

[0028] Furthermore, in describing the present invention, if it is determined that a specific description of a related known configuration or function would likely obscure the gist of the invention, such detailed description will be omitted.

[0029] Since embodiments of the present invention are provided to give a more complete explanation to an ordinary person of the art, the shapes and sizes of the components in the drawings may be exaggerated, omitted, or shown schematically for the sake of clarity. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes and proportions.

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

[0031] Figure 2 is a diagram showing an electrode sheet inside a drying oven according to an exemplary embodiment.

[0032] Figure 3 is a diagram showing an electrode sheet drying apparatus according to an exemplary embodiment.

[0033] Referring to Figures 1 to 3, the electrode sheet drying apparatus 100 may include a drying oven 101, a hot air supply device 102, a flow path 110, a plurality of injection 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 in the drying oven 101 with hot air supplied from the hot air supply device 102. The hot air supply device 102 is the drying means. The drying means is not limited to any means that supplies 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 the current collector 202. The electrode sheet 200 may include a coated portion on the current collector 202 where the slurry 201 is applied, and an uncoated portion on the current collector 202 where the slurry 201 is not applied.

[0035] The electrode sheet drying apparatus 100 can provide water that has traveled through a flow path 110 to a moving electrode sheet 200. The flow path 110 may include an inlet 110_1 into which water flows and an outlet 110_2 into which water flows out. Multiple spray nozzles 120 are arranged inside the drying oven 101 and can spray water onto the moving electrode sheet 200. According to an exemplary embodiment, the multiple spray nozzles 120 may be arranged along the width direction of the electrode sheet 200. The multiple spray nozzles 120 are connected to the outlet 110_2 of the flow path 110 so that water that has traveled through the flow path 110 can be sprayed onto the electrode sheet 200 through the multiple spray nozzles 120. According to an exemplary embodiment, water can be sprayed onto the uncoated portion of the electrode sheet 200.

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

[0037] Figure 4 is a cross-sectional perspective view showing a flow path including a PTC heater according to an exemplary embodiment.

[0038] Figure 5 is a cross-sectional perspective view showing a flow path including a PTC heater according to another exemplary embodiment.

[0039] Referring to Figures 4 and 5, the flow path 110 may contain one or more PTC heaters 113. The PTC heaters 113 may be electric heating elements using PTC thermistors. A PTC thermistor may be a resistor whose resistance changes with high sensitivity in response to temperature changes. For example, its resistance increases as the temperature rises, thereby limiting the flow of current. This makes it easy for the PTC heaters 113 to heat the 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. This allows the electrode sheet drying apparatus 100 to provide the electrode sheet 200 with water that has a constant temperature range. Furthermore, heating the water moving through the flow path 110 using the PTC heater 113 can shorten the heating time compared to heating all 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 the water moving within the flow path 110. The inner pipe 111 may contain a thermally conductive material. The outer pipe 112 may be configured so that the PTC heater 113 is not affected by the external temperature. The outer pipe 112 may also be configured so that the heat emitted from the PTC heater 113 does not escape 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 direction of extension 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 constant intervals along the direction of extension of the flow path 110. This allows the plurality of PTC heaters 113 to be provided at equal intervals within the flow path 110 and to heat the water uniformly without enclosing the entire inner piping 111.

[0043] According to an exemplary embodiment, the length of each of the multiple PTC heaters 113 can be in the range of approximately 20% to 80% of the total length of the flow path 110. According to an exemplary embodiment, the length of each of the multiple PTC heaters 113 can be in the range of approximately 30% to 70% of the total length of the flow path 110. The PTC heaters 113 are characterized by their rapid heating, and the multiple PTC heaters 113 can be arranged at equal intervals within the flow path 110. This allows for uniform and rapid heating of the water even if the length of each of the multiple PTC heaters 113 is shorter than the total length of the flow path 110. Furthermore, by reducing the area occupied by the PTC heaters 113 within the flow path 110, energy efficiency can also be improved.

[0044] According to exemplary embodiments, the flow path 110 may further include a plurality of heat-conducting blades 114 projecting inward. The plurality of heat-conducting blades 114 may be arranged at equal intervals along the circumferential direction of the flow path 110. The plurality of heat-conducting blades 114 may be arranged at equal intervals along the extension direction of the flow path 110. This allows the plurality of heat-conducting blades 114 to rapidly transfer heat generated by the plurality of PTC heaters 113 to the water.

[0045] According to an exemplary embodiment, the multiple heat-conducting blades 114 may have a shape in which their thickness decreases along the inward direction of the flow path 110. This can prevent obstruction of the movement of water within the flow path 110. The extended form of the multiple heat-conducting blades 114 may be a linearly extended form or a curved extended form, as shown in Figure 5.

[0046] The material of the multiple heat-conducting blades 114 is not significantly limited, as long as it is a material capable of transmitting thermal energy. For example, the multiple heat-conducting blades 114 may include metals. According to an exemplary embodiment, the multiple heat-conducting 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 it toward the uncoated areas of the electrode sheet 200 and prevent it from being sprayed into the coated areas. This can prevent cracks and wrinkles from occurring in the uncoated areas, reduce electrode defects and improve electrode stability.

[0048] (Second Embodiment) Figure 6 is a drawing showing an electrode sheet drying apparatus 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] A first temperature sensor 140_1 can measure the temperature of water flowing into the flow path 110. A second temperature sensor 140_2 can measure the temperature of water heated by the PTC heater 113 downstream of the PTC heater 113. Based on the water temperatures measured by the first temperature sensor 140_1 and the second temperature sensor 140_2, it can be determined whether or not to activate the PTC heater 113. 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 decide 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 the 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, thereby measuring the temperature of the heated water. The control unit 150 may stop the operation of the PTC heater 113 if the water temperature measured by the second temperature sensor 140_2 is in the range of approximately 70°C to approximately 90°C. This allows the water temperature to be maintained within a constant 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 control unit 170. The storage tank 160 may provide a place for water to be stored before it is moved to the flow path 110. The flow rate control unit 170 may measure the flow velocity and flow rate of water. Based on the data detected by the flow rate control unit 170, the intensity of the pump 130 may be adjusted.

[0054] <Method for drying electrode sheets> (First Embodiment) Figure 7 is a flowchart showing the method for drying the electrode sheet according to the first embodiment.

[0055] Referring to Figures 3, 6, and 7, the electrode sheet drying method may include the steps of: a pump 130 supplying water to a flow path 110 having an inlet 110_1 and an outlet 110_2; a first temperature sensor 140_1 measuring the temperature of the water flowing into the inlet 110_1; a control unit 150 determining, based on the water temperature, whether it is necessary to activate the PTC heater 113; and a control unit 150 activating (on) the PTC heater 113 contained within the flow path 110 when it has determined that it is necessary to activate the PTC heater 113. According to an exemplary embodiment, the electrode sheet drying method may further include the step of spraying water, whose temperature has risen via 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, wherein 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 multiple spray nozzles 120 can be in the range of approximately 70°C to 90°C.

[0056] Step P110, in which the pump 130 supplies water to the flow path 110 having an inlet 110_1 and an 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. A flow rate control unit 170 located in the flow path 110 may detect the flow velocity and flow rate of the water flowing into the flow path 110.

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

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

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

[0060] Referring to Figures 3, 6, and 8, the method for drying the electrode sheet may further include, after the step of operating the PTC heater 113, a step P160 in which a second temperature sensor 140_2 located downstream of the PTC heater 113 measures the temperature of the water, and a step P170 in which the control unit 150 determines, based on the temperature of the water, whether it is necessary to operate the PTC heater 113. 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, a step P180 may be performed in which the control unit 150 turns off the operation of the PTC heater 113. 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, a step P180 may be performed in which the control unit 150 turns off the operation of the PTC heater 113.

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

[0062] 100: Drying device for electrode sheets 101: Drying oven 102:Hot air supply device 110: Flow channel 110_1: Inlet 110_2: Outlet 111: Internal piping 112:Outside piping 113: PTC heater 114: Thermally conductive blade 120: Spray 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 an electrode sheet formed by applying slurry onto an electrode current collector, A plurality of spray nozzles are arranged inside the drying oven, positioned 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 injection nozzles, The pump includes a pump that moves the water through the flow path, The aforementioned flow path includes one or more positive temperature coefficient heaters inside, and is used as a drying apparatus for electrode sheets.

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

3. The electrode sheet drying apparatus 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 total length of the flow path.

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

5. The flow path has a double-pipe configuration including an inner pipe and an outer pipe surrounding the inner pipe. The electrode sheet drying apparatus according to any one of claims 1 to 3, wherein the positive temperature coefficient heater is located between the inner piping and the outer piping.

6. The electrode sheet drying apparatus according to any one of claims 1 to 3, wherein the flow path includes a plurality of heat-conductive blades protruding inward.

7. The electrode sheet drying apparatus further includes a control unit, The pump includes a first temperature sensor, The electrode sheet drying apparatus according to any one of claims 1 to 3, wherein the control unit adjusts the operation of the positive temperature coefficient heater based on the water temperature measured by the first temperature sensor.

8. Further including a first temperature sensor and a second temperature sensor, The first temperature sensor measures the temperature of the water flowing into the flow path, The electrode sheet drying apparatus according to any one of claims 1 to 3, 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 apparatus according to claim 8, wherein the second temperature sensor is included in the flow path.

10. The electrode sheet drying apparatus 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 apparatus further includes a control unit, The electrode sheet drying apparatus according to claim 8, wherein the control unit determines whether to activate the positive temperature coefficient heater based on the water temperature detected by the first temperature sensor and the second temperature sensor.

12. The electrode sheet drying apparatus according to any one of claims 1 to 3, wherein the water sprayed onto the electrode sheet has a temperature in the range of 50°C to 90°C.

13. The present invention further includes a storage tank in which the water supplied to the plurality of injection nozzles is stored, The electrode sheet drying apparatus according to any one of claims 1 to 3, wherein the flow path further includes a flow control unit.

14. The pump supplies water to a flow path having an inlet and an outlet, The first temperature sensor measures the temperature of the water flowing into the inlet, The steps include: determining the need for the control unit to operate the positive temperature coefficient heater based on the water temperature; When the control unit determines that it is necessary to activate the positive temperature coefficient heater, the control unit activates the positive temperature coefficient heater located inside the flow path, The step includes spraying the water, whose temperature has risen via the positive temperature coefficient heater, onto an electrode sheet from a plurality of injection nozzles connected to the outlet of the flow path, A 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. The step of activating the positive temperature coefficient heater further includes a step of measuring the water temperature using a second temperature sensor located in the flow path and downstream of the positive temperature coefficient heater, The method for drying an electrode sheet according to claim 14, wherein the control unit stops the operation of the positive temperature coefficient heater when the temperature of the water measured by the second temperature sensor is in the range of 70°C to 90°C.

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