Electrode drying device and electrode drying method

Abstract

The present invention disclosed herein provides an electrode drying apparatus comprising: a heating chamber having an electrode inlet and an electrode outlet in which an electrode is mounted so as to be movable between the electrode inlet and the electrode outlet; a heating member installed in the heating chamber to heat the electrode in the last heating zone before the electrode exit; and a control unit that variably controls an output of the heating member in response to a temperature change according to an operation time of the electrode drying apparatus when the temperature of the electrode measured between the last heating zone and the electrode outlet changes. The invention also provides an electrode drying method executed by the electrode drying device.

Description

Technical Field

[0001] The invention relates to an electrode drying device and an electrode drying method.

[0002] Specifically, the present invention relates to an electrode drying device and method for variably controlling the output of a heating member that heats an electrode in response to a change in an initial temperature of the electrode, which is repeatedly driven and stopped in a heating chamber configured to dry the electrode.

[0003] This application claims priority to Korean Patent Application No. 10-2023-0026101 filed on February 27, 2023, which is incorporated herein in its entirety. Background Art

[0004] The secondary battery is manufactured by placing an electrode assembly in a battery case and injecting an electrolyte. The electrode assembly has a structure in which a positive electrode and a negative electrode are stacked with a separator interposed therebetween.

[0005] Electrodes such as positive electrodes or negative electrodes are manufactured by coating a current collector with an active material slurry. After the coating process, the electrode is dried to remove moisture from the active material slurry. In addition, in order to remove moisture that is inevitably mixed into the electrode during the secondary battery manufacturing process, the electrode is dried in subsequent processes such as a slotting process or even other sub-processes after the coating process.

[0006] In the drying process of the electrode, the electrode is dried in the heating chamber while being conveyed in a roll-to-roll state. The electrode installed in the heating chamber is dried by a heating member installed in the heating chamber while being repeatedly driven and stopped. The stopped electrode is accelerated until a target driving speed is reached, and is driven at a constant speed when the target driving speed is reached.

[0007] In addition, it is important to stabilize the temperature of the electrode in the heating chamber in a short time in terms of the quality stability of the electrode and the operating productivity. Starting from the electrode near the electrode outlet, the electrode installed in the heating chamber is continuously discharged through the electrode outlet of the heating chamber. The electrode passes through the last heating zone installed before the electrode outlet. The time point when the electrode passes through the last heating zone can vary depending on the position of the electrode, resulting in a change in the temperature of the electrode when the electrode is started to be discharged. The temperature of the electrode can also vary depending on the total number or position of the heating zones in the heating chamber, the driving speed of the electrode or the change in the driving speed.

[0008] When it takes a long time for the temperature of the electrode to stabilize, it means that the quality of the electrode manufactured during the temperature stabilization period is unstable. During operation, the electrode is repeatedly stopped and driven in the heating chamber, so when the time required to stabilize the electrode temperature increases, the number of electrodes with unstable quality will also increase. In some cases, electrodes with unstable quality may cause defects and should be removed. In this case, the overall operating efficiency will inevitably decrease.

[0009] Figures 1 to 3 is a graph showing the principle of controlling the output of a heating member in a related art electrode drying process.

[0010] like Figure 1 As shown, in the electrode drying process of the prior art, in order to make the temperature of the electrode reach the target temperature in a short time, when the electrode starts to be driven, the initial output X of the heating member installed at the last heating zone will increase in response to the increase of the electrode driving speed. In addition, at the time point when the driving speed reaches the target driving speed, the output of the heating member is set to a constant speed output Y, and the electrode is heated according to the constant speed output Y after this time point.

[0011] Figure 2 and Figure 3 The relationship between the temperature change of the electrode and the output change is shown. Figure 2 and Figure 3 It can be seen that the time required to reach the target driving speed is T1, and the device operation time T2 to reach the electrode temperature stabilization is longer than time T1. In other words, it takes a relatively long device operation time to reach the electrode temperature stabilization. When the time required to reach the electrode temperature stabilization can be reduced to Figure 3 At the target time t1, the quality stability and operation productivity of the electrode will be significantly improved.

[0012] [Prior art literature]

[0013] [Patent document]

[0014] Korean Patent Publication No. 10-2022-0068179 Summary of the invention

[0015] Technical issues

[0016] To solve the above problems, the present invention is directed to an electrode drying device and method for variably controlling the output of a heating member by considering the condition of an electrode in a heating chamber just before driving the electrode, the arrangement of heating zones, etc.

[0017] Technical Solution

[0018] According to an embodiment of the present invention, an electrode drying device includes: a heating chamber having an electrode inlet and an electrode outlet, wherein the electrode is installed to be driven between the electrode inlet and the electrode outlet; a heating member installed in the heating chamber to heat the electrode at a last heating zone before the electrode outlet; and a controller configured to variably control the output of the heating member in response to a temperature change of the electrode measured between the last heating zone and the electrode outlet according to an operating time of the electrode drying device.

[0019] The electrode may be installed in the heating chamber so that a driving direction of the electrode changes at least once.

[0020] When the electrode stops in the heating chamber, the electrode may be accelerated at a specific rate until a target driving speed is reached.

[0021] A plurality of heating zones may be provided in the heating chamber, each heating zone corresponding to one of the driving directions of the electrode, and the last heating zone may be the rearmost heating zone among the plurality of heating zones.

[0022] The controller corrects the temperature of the electrode by increasing or decreasing the output of the heating member inversely to changes in the measured temperature of the electrode.

[0023] The controller may vary the output of the heating member until the measured temperature of the electrode remains controlled, and the resulting output of the heating member may remain constant to correspond to the temperature of the electrode after the temperature of the electrode remains constant.

[0024] When the measured temperature of the electrode increases, the output of the heating member is controlled by at least one of the following means:

[0025] i) reducing the output of the heating member in proportion to the rate of increase in the temperature of the electrode to prevent the temperature of the electrode from excessively increasing; and

[0026] ii) reducing the output of the heating member in proportion to the rate of increase in the temperature of the electrode to maintain the target temperature of the electrode.

[0027] When the measured temperature of the electrode decreases, the output of the heating member may be increased in proportion to the rate of decrease in the temperature of the electrode so that the temperature of the electrode approaches a target temperature.

[0028] The controller may set the initial output of the heating member to be inversely proportional to an initial temperature of the electrode measured between the last heating zone and the electrode outlet.

[0029] The controller may set an initial output of the heating member to be proportional to a target driving speed of the electrode.

[0030] Another aspect of the present invention provides a method for drying an electrode that is initially driven in a stationary state in a heating chamber, wherein the output of a heating member at a last heating zone in the heating chamber is variably controlled in response to a temperature change of the electrode measured between the last heating zone and an electrode outlet of the heating chamber according to the operation time of the electrode drying device.

[0031] Specifically, when the measured temperature of the electrode changes, the temperature change of the electrode is corrected by reducing or increasing the output of the heating member inversely to the temperature change of the electrode.

[0032] In the method, the output of the heating member may be varied until the measured temperature of the electrode is maintained controlled, and the resulting output of the heating member may be maintained constant to correspond to the temperature of the electrode after the temperature of the electrode is maintained constant.

[0033] In the method, the initial output of the heating member may be arranged to be inversely proportional to the initial temperature of the electrode measured between the last heating zone and an electrode outlet.

[0034] In the method, an initial output of the heating member may be set proportional to a target drive speed of the electrode measured between the last heating zone and the electrode outlet.

[0035] Beneficial Effects

[0036] According to the present invention, by controlling the output of the heating member at the beginning of driving the electrode in response to the initial temperature change of the electrode, the time required for the electrode temperature to be stabilized can be significantly reduced.

[0037] As a result, the quality stability and operational productivity of the electrodes will be significantly improved.

[0038] Furthermore, by setting the initial output of the heating member in response to the initial temperature of the electrode in the heating chamber or the target driving speed of the electrode, the deviation in the time required to achieve stabilization of the electrode temperature can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figures 1 to 3 is a graph showing a principle of controlling the output of a heating member in an electrode drying process of the related art.

[0040] Figure 4 : is a schematic diagram illustrating an example of the electrode drying device of the present invention.

[0041] Figure 5is a graph showing the change in electrode temperature over time when the electrode is heated by a high-output heating member.

[0042] Figure 6 is a graph showing the variation of electrode temperature as a function of the time required to pass through the last heating zone, the run time, and the linear speed.

[0043] Figure 7 is a graph showing output variation of a heating member for compensating for temperature variation.

[0044] Figure 8 is a graph showing a temperature stabilization process of an electrode according to one embodiment of the present invention.

[0045] Fig. 9 is a graph showing output variation and the effect of shortening the temperature stabilization time according to one embodiment of the present invention.

[0046] Fig.10 is a flow chart of an electrode drying process according to the present invention.

[0047] Fig.11 is a graph showing the electrode initial temperature and the electrode temperature change according to the output.

[0048] Fig.12 is a graph showing an initial output control principle according to another embodiment of the present invention.

[0049] Fig.13 is a graph showing a change in electrode temperature according to a target driving speed of the electrode and an output of a heating member.

[0050] Fig.14 is a graph showing an initial output control principle according to another embodiment of the present invention. DETAILED DESCRIPTION

[0051] Hereinafter, the present invention will be described in detail. Before describing the present invention, the terms or expressions used in this specification and claims should not be understood as being limited to the meanings generally understood or defined in common dictionaries, but should be understood based on the inventors of the present application can appropriately define the terms or expressions to best explain the principles of the present invention, according to the meanings and concepts corresponding to the present invention.

[0052] It should be understood that the terms "include" and / or "comprising" used herein refer to the presence of the features, integers, steps, operations, elements, components or combinations thereof, but do not exclude the presence or addition of one or more features, integers, steps, operations, elements, components or combinations thereof. It should be understood that when an element or component is referred to as being "connected" to another element or component, the element or component is directly or indirectly connected to the other element or component.

[0053] Terms such as “on” or “below”, “front” or “back”, or “placed” or “arranged” used herein are not intended to limit the present invention but should be understood to provide examples of terms indicating positions or directions.

[0054] According to one embodiment of the present invention, an electrode drying device includes: a heating chamber having an electrode inlet and an electrode outlet, wherein an electrode is installed to be driven between the electrode inlet and the electrode outlet; a heating member installed in the heating chamber to heat the electrode at a last heating zone before the electrode outlet; and a controller, which variably controls the output of the heating member in response to a temperature change of the electrode measured between the last heating zone and the electrode outlet according to an operating time of the electrode drying device.

[0055] Another aspect of the present invention provides a method for drying an electrode that is initially driven in a stationary state in a heating chamber, wherein the output of a heating member at a last heating zone in the heating chamber is variably controlled in response to a temperature change of the electrode measured between the last heating zone and an electrode outlet of the heating chamber according to the operation time of the electrode drying device.

[0056] Embodiments of the present invention

[0057] Hereinafter, the present invention will be described in detail.

[0058] (First Embodiment)

[0059] During the manufacturing process of the secondary battery, the electrode may be dried to remove moisture from the electrode. As described above, during the electrode drying process, quickly stabilizing the initial temperature of the electrode is very important for operation productivity and quality stability.

[0060] The electrode drying device 100 of the present invention includes: a heating chamber having an electrode inlet 11a and an electrode outlet 11b, wherein the electrode 1 is installed to be driven between the electrode inlet 11a and the electrode outlet 11b; a heating component installed in the heating chamber to heat the electrode 1 at the last heating zone Z3 before the electrode outlet 11b; and a controller that variably controls the output of the heating component in response to the temperature change of the electrode 1 measured between the last heating zone Z3 and the electrode outlet 11b according to the operating time of the electrode drying device 100.

[0061] Figure 4 is a schematic diagram illustrating an example of the electrode drying device 100 of the present invention.

[0062] The heating chamber 10 is a heat drying space for the electrode 1, in which the electrode 1, the heating chamber 20 and the guide roller R are arranged. Figure 4 The chamber wall 11 is illustrated, and the space inside the chamber wall 11 is the heat drying space. In some cases, the chamber wall 11 may be referred to as a chamber frame. For ease of explanation, the chamber wall 11 on the front surface of the heating chamber 10 is not shown, but may be formed on the front surface of the heating chamber 10 to form a sealed heat drying space. An entrance door (not shown) may be formed on one side of the chamber wall 11, which is used for loading the heating chamber 10 into the heating chamber 10 or for maintenance of the equipment. An electrode inlet 11a for introducing the electrode 1 and an electrode outlet 11b for discharging the electrode 1 after the electrode 1 is dried are provided at the heating chamber 10. Although Figure 4 The electrode inlet 11a and the electrode outlet 11b are illustrated as being disposed at the bottom of the heating chamber 10, but the positions of the electrode inlet 11a and the electrode outlet 11b are not limited thereto, and the electrode inlet 11a and the electrode outlet 11b may be disposed at the top of the heating chamber 10. However, in consideration of the arrangement relationship between the heating member 20 in the heating chamber 10, the frame supporting the heating member 20, and the driving unit driving the frame, or the connection with other devices outside the heating chamber 10, it is preferable to convey the electrode 1 along a symmetrical driving path in the heating chamber 10. Therefore, it is preferable to form the electrode inlet 11a and the electrode outlet 11b at both sides of the top or bottom of the chamber wall 11 so as to face each other, thereby matching the symmetrical driving path of the electrode 1.

[0063] The electrode 1 to be dried is driven in a roll-to-roll state in the heating chamber 10. That is, the electrode 1 is supported and the direction of the electrode 1 is changed by the guide roller R, so that the electrode 1 is conveyed along a specific driving path in the roll-to-roll state. In addition, an unwinder and a rewinder (not shown) configured to wind the electrode 1 may be provided outside the heating chamber 10 to drive the electrode 1 in the roll-to-roll state.

[0064] The heating member 20 may be a hot air injection device or an infrared heater. However, the type of the heating member 20 is not limited as long as one or both sides of the electrode 1 can be properly heated by a heat transfer method such as conduction, convection, and radiation. In one embodiment of the present invention, an example of an infrared heater being used as the heating member 20 is shown. The infrared heater may include an infrared lamp 21 that emits infrared rays to the electrode 1, and a support frame 22 that is configured to support or fix the infrared lamp 21.

[0065] The heating member 20 may be installed to face the surface or the back surface of the electrode 1 extending between the guide rollers R. Alternatively, a pair of heating members 20 may be installed to face both the surface and the back surface of the electrode 1 .

[0066] In order to improve the efficiency of drying the electrode 1 in a limited space, the electrode 1 can be installed in the heating chamber 10 so that the driving direction of the electrode 1 can be changed at least once. For example, the driving path of the electrode 1 can be formed so that the horizontal driving component and the vertical driving component are alternately arranged in the heating chamber 10. Figure 4 , three horizontal driving components and two vertical driving components are alternately arranged. However, the configuration of the driving path in the heating chamber 10 is not limited thereto, and various other types of driving paths may be provided in the heating chamber 10 as long as the electrode 1 can be dried efficiently.

[0067] A guide roller R may be provided in the heating chamber 10 to change the direction of the electrode 1. The guide roller R is a direction conversion roller that supports the electrode 1 and changes the driving direction of the electrode 1 when driven. In order to increase the driving path of the electrode 1 in a limited space such as the heating chamber 10, the electrode 1 should not be driven in only one direction. In the present embodiment, the guide roller R is arranged so that the driving path of the electrode 1 includes a horizontal driving portion and a vertical driving portion that are alternately formed. Therefore, when the direction of the electrode 1 is changed in a limited space, the electrode 1 is conveyed along the increased driving path, thereby improving the drying efficiency. In addition, when the driving path is increased, the space in which the heating member 20 can be placed also increases, so more heating members 20 can be arranged to enhance the heating effect. The arrangement of the guide roller R and the correspondingly configured electrode driving path are not limited to Figure 4 , you can also configure Figure 4 Different U-shaped paths or paths with repeated U-shapes.

[0068] A plurality of heating zones Z1, Z2 and Z3 may be provided in the heating chamber 10 corresponding to the electrode driving direction. In the heating zones Z1, Z2 and Z3, a plurality of heating members 20 as described above are installed opposite to the electrode 1, thereby heating the electrode 1. Figure 4 As shown, the heating zones Z1, Z2 and Z3 can be installed parallel to the driving directions of the electrode 1. Figure 4In the example of, the first heating zone Z1 located at the electrode inlet 11a, the third heating zone (the last heating zone) Z3 located at the electrode outlet 11b, and the second heating zone Z2 located between the first heating zone Z1 and the third heating zone Z3 are arranged in the heating chamber 10. The first heating zone Z1 is installed at a position where the direction of the electrode 1 introduced into the electrode inlet 11a and driven horizontally is changed so that the electrode 1 is driven vertically. The second heating zone Z2 is installed at a position where the direction of the electrode 1 driven vertically is changed to the direction in which the electrode 1 is driven horizontally. The third heating zone Z2 is installed at a position where the direction in which the electrode 1 is driven horizontally is changed to the direction in which the electrode 1 is driven vertically. The direction of the electrode 1 is changed by the third heating zone Z3, so that the electrode 1 is driven horizontally and discharged through the electrode outlet 11b. There are non-heating sections NH between the heating zones Z1, Z2 and Z3, and the heating member 20 is not placed on these non-heating sections NH.

[0069] The arrangement of the heating zones Z1, Z2 and Z3 is not limited to the above examples, and the heating zones Z1 to Z3 can be arranged in different forms according to the size and shape of the heating chamber 10, the length and shape of the electrode driving path, etc. In any case, at least one heating zone is provided in the heating chamber 10. That is, the electrode 1 driven in the heating chamber 10 passes through one or more heating zones and is then discharged through the electrode outlet 11b. Therefore, the heating chamber 10 must include at least one heating zone (for example, the last heating zone Z3). When the heating zones Z1, Z2 and Z3 are installed in the heating chamber 10, the last heating zone Z3 is the rearmost heating zone among the heating zones Z1, Z2 and Z3.

[0070] The electrode is manufactured and processed on a series of continuous production lines. Therefore, the electrode 1 is connected to other equipment before and after the heating chamber 10. When other equipment is running or stopped, the electrode 1 can be repeatedly driven and stopped in the heating chamber 10. Alternatively, the electrode 1 can be repeatedly driven and stopped in the heating chamber 10 according to the drying progress of the electrode drying device 100. For example, when the unwinder or rewinder outside the heating chamber 10 rotates, the electrode 1 wound around the unwinder or rewinder starts to be driven in a stationary state. The electrode 1 is accelerated in a stationary state until the target drive speed is reached. For example, the electrode 1 in a stationary state can be accelerated at a specific rate until the target drive speed is reached. In addition, the heating member 20 in the heating chamber 10 can be repeatedly heated or stopped according to the driving or stopping of the electrode 1. When the electrode drying device 100 stops (when the heating member 20 and the electrode driving component stop), the electrode 1 stops in the heating chamber 10. When the electrode drying device 100 is started (when the heating member 20 and the electrode driving part are started), the electrode 1 is driven and discharged from the electrode outlet 11b. The operation time of the electrode drying device 100 is calculated from the time point when the electrode drying device 100 is started.

[0071] The temperature of the electrode 1 that is dried and discharged from the electrode outlet 11b of the heating chamber 10 does not stabilize immediately from the time when the electrode drying device 100 is started. Figures 1 to 3 As shown, by controlling the output of the heating member 20 (feedback control), especially the output of the heating member 20 at the last heating zone Z3, the temperature of the electrode 1 can be kept constant only after a period of stabilization time. As described above, the temperature stabilization time of the dried electrode 1 has a significant influence on the operational productivity and quality stability of the electrode 1, so it is important to effectively shorten the temperature stabilization time.

[0072] The time point when the electrode 1 reaches the electrode outlet 11b while passing through the last heating zone Z3 depends on the initial position of the electrode 1 in the heating chamber 10. Therefore, the temperature of the electrode 1 passing through the last heating zone Z3 will continuously change.

[0073] In addition, when the electrode 1 is initially driven, the driving speed of the electrode 1 varies with time. Therefore, the time required to pass through the final heating zone Z3 depends largely on the initial position of the electrode 1, resulting in a temperature change of the electrode 1.

[0074] In addition, according to the arrangement of the heating zones Z1, Z2, and Z3, a non-heating section NH is formed in the heating chamber 10. The temperature of the electrode 1 passing through the non-heating section NH may be relatively low.

[0075] Furthermore, when the additional heating zones Z1 and Z2 are arranged before the final heating zone Z3, the temperature of the electrode 1 passing through the final heating zone Z3 after passing through the additional heating zones Z1 and Z2 may be relatively high.

[0076] As described above, the temperature of the electrode passing through the last heating zone Z3 at the start of driving the electrode is not constant due to various variables such as the position of the electrode in the heating chamber 10, the positions of the heating zones Z1, Z2 and Z3, the time required to pass through the heating zones Z1, Z2 and Z3, the driving speed, etc. Therefore, the temperature of the electrode discharged through the electrode outlet 11b is also not constant.

[0077] The present invention is characterized in that the electrode temperature is controlled as quickly as possible when the electrode starts to be driven, thereby improving the operation productivity and quality stability.

[0078] The controller 30 of the present invention variably controls the output of the heating member 20 in response to a temperature change of the electrode 1 measured between the last heating zone Z3 and the electrode outlet 11 b according to the operation time of the electrode drying device 100 .

[0079] Since the temperature of the electrode 1 passing through the last heating zone Z3 changes, it is necessary to accurately measure the temperature of the electrode 1 at this point. Since the distance between the last heating zone Z3 and the electrode outlet 11b is short, a certain point between the last heating zone Z3 and the electrode outlet 11b can be set as a temperature measurement point. Preferably, the point immediately after the last heating zone Z3 can be set as a temperature measurement point. At this temperature measurement point, the temperature of the electrode 1 is measured by a temperature measuring member S. Various types of temperature sensors can be used as temperature measuring members S. For example, thermocouples that detect electromotive force at a specific temperature, resistance temperature sensors (RTDs) and thermistors that detect resistance, liquid thermometers or bimetallic temperature sensors whose states change with temperature can be used as contact temperature sensors. However, when measuring temperature by a contact temperature sensor, the electrode 1 may be negatively affected, so it is preferred to use a non-contact temperature sensor. For example, an infrared thermometer that detects temperature using infrared rays can be used as a non-contact temperature sensor.

[0080] Temperature measuring member S may be installed at the exit of heating zones Z1, Z2 and Z3. By measuring the temperature of electrode 1 passing through each of heating zones Z1, Z2 and Z3 by temperature measuring member S, the relationship between heating of heating member 20 and the temperature of electrode 1 may be grasped.

[0081] In this embodiment, a non-contact temperature sensor (infrared thermometer) is installed at a temperature measurement point immediately after the last heating zone Z3 to measure the electrode temperature at that point.

[0082] When the electrode 1 is initially driven, the temperature of the electrode 1 is relatively low, and thus the electrode 1 can be heated by the heating member 20 with a relatively high output to be heated quickly.

[0083] exist Figure 4 middle, and Indicates the location of the electrode. represents the position of the electrode outside the electrode outlet, represents the position of the electrode at the exit of the last heating zone Z3 (particularly between the last heating zone Z3 and the electrode exit), represents the position of the electrode at the entrance of the last heating zone Z3, Represents the position of the electrode in the non-heating section just before the second heating zone Z2.

[0084] Figure 5 is a graph showing a change in electrode temperature according to an operation time of the electrode drying device 100 when the electrode is heated by the heating member 20 having a fixed high output.

[0085] Figure 5The first part I of the graph shows the position of the electrode after the last heating zone Z3 before the electrode operating device is operated. That is, the electrode 1 is not heated, so the temperature of the electrode 1 is low. Therefore, by setting the output of the heating member 20 high at the last heating zone Z3, the temperature of the electrode rises rapidly.

[0086] Figure 5 The second part II of the graph shows that when the electrode is continuously driven and passes through the last heating zone Z3, the electrode temperature immediately after the last heating zone Z3 gradually increases. For example, when the electrode passes through the last heating zone Z3, the position at the entrance of the last heating zone Z3 before the device is operated is The electrode temperature at the temperature measurement point is too high because the electrode stays in the last heating zone Z3 for the longest time and has been sufficiently heated by the high-output heating member 20. That is, when the operation time of the electrode drying device is XX seconds, the electrode temperature measured at the temperature measurement point is the highest.

[0087] Figure 5 The third part III of the graph shows the electrode temperature measured at the temperature measurement position and the temperature change when the operation time of the electrode drying device is ZZ seconds. Electrode 1 is the position on the non-heating section NH between the last heating zone Z3 and the second heating zone Z2 before the device is operated. In addition, when the electrode in the non-heating section NH passes through the last heating zone Z3, the speed of the electrode 1 increases. In this case, the time required for the electrode 1 to pass through the last heating zone Z3 is YY seconds less than the XX seconds required for the electrode in the second section II. Therefore, when the electrode 1 in this section reaches the temperature measurement point, the temperature of the electrode 1 starts to decrease from the excessively high temperature.

[0088] Figure 5 The fourth part IV of the graph shows that the temperature of the electrode 1 rises again. When there is no heating zone before the last heating zone Z3, the temperature of the electrode steadily decreases due to the increase in the driving speed of the electrode. That is, as the electrode 1 passes through the last heating zone Z3 at a high speed, the electrode temperature measured at the temperature measurement point stabilizes and starts to decrease from the excessively high temperature state.

[0089] However, in practice, in many cases, the heating chamber is provided with an additional heating zone such as the second heating zone Z2 to improve the productivity of the drying operation. In this case, even when the driving speed of the electrode is increased, the electrode passing through the additional heating zone Z2 passes through the last heating zone Z3 and reaches the temperature measurement point. Therefore, the electrode is additionally heated, so that the electrode temperature at the temperature measurement point rises slowly again.

[0090] exist Figure 5In the fifth section V of the graph of , the driving speed of the electrode reaches the target driving speed, and the driving speed and temperature of the electrode heated in the additional heating zone Z2 and the last heating zone Z3 are balanced. In the fifth section V, the temperature of the electrode 1 is finally stabilized.

[0091] As described above, the temperature of the electrode 1 continuously measured at the temperature measurement point varies depending on the operating time of the device. The trend of temperature variation may vary depending on the arrangement of the heating zones Z1, Z2, and Z3 in the heating chamber, the time required to pass through the last heating zone Z3, and the initial temperature of the electrode. However, the variation of the initial temperature of the electrode drying device used recently inevitably includes such variation. In view of such variation, it takes a considerable time for the temperature of the electrode to stabilize.

[0092] Figure 6 is a graph showing changes in electrode temperature according to the time required to pass through the last heating zone Z3, the device operation time, and the electrode driving speed.

[0093] and Figure 5 Similar, in Figure 6 In the first part (i) of the graph where the electrode does not pass through the final heating zone Z3, the temperature of the electrode is the lowest.

[0094] exist Figure 6 In the second part (ii) of the graph of FIG. 1 , in which the time required to pass through the last heating zone Z3 continues to increase, the temperature of the electrode rises to an excessively high temperature state.

[0095] exist Figure 6 The graph of FIG. 1 shows that in the third part (iii) where the electrode located in the non-heating section NH passes through the last heating zone Z3, the electrode passes through the last heating zone Z3 but is not sufficiently heated due to the increase in its driving speed. Therefore, the temperature of the electrode decreases.

[0096] exist Figure 6 After the third part (iii) of the graph of , when the linear speed increases and reaches the target driving speed, the temperature of the electrode steadily decreases. Figure 6 In FIG. 1 , an example in which the temperature of the electrode is increased again due to heating in the additional heating zone Z2 is not shown.

[0097] As described above, in the present invention, the output of the heating member 20 is variably controlled in response to the change in the electrode temperature measured between the last heating zone Z3 and the electrode outlet 11b according to the operation time of the electrode drying device. When the electrode in the heating chamber is heated by the heating member 20 with a fixed output, as described above, the temperature of the electrode at the temperature measurement point changes in a pattern of rise-fall-stabilization (when the influence of the additional heating zone Z2 is excluded) or rise-fall-rise-stabilization (when the influence of the additional heating zone Z2 is considered). In the present invention, in response to each time the electrode temperature changes, the output of the heating member 20 installed at the last heating zone Z3 is changed from a fixed output to a variable output, thereby shortening the time required for the electrode temperature to finally stabilize.

[0098] Figure 7 is a graph showing the output change of the heating member 20 for compensating for the temperature change. Figure 7 In the figure, the solid line represents the temperature change of the electrode, while the dotted line represents the output change. Figure 7 As shown, the controller 30 can increase or decrease the output of the heating member 20 inversely with the temperature change of the electrode 1. Specifically, when the temperature of the electrode increases in proportion to the time required to pass through the last heating zone Z3, the output of the heating member 20 increases in proportion to the increase rate.

[0099] Thereafter, as the temperature of the electrode 1 gradually decreases as the electrode 1 passing through the non-heating section NH passes through the final heating zone Z3 at a high speed, the output of the heating member 20 decreases in proportion to the rate of decrease. When the additional heating zones Z1 and Z2 are not considered, the temperature of the electrode steadily decreases, and thus the output of the heating member 20 can be controlled to steadily increase accordingly.

[0100] In the section where the electrode temperature is increased again due to the heating of the additional heating zones Z1 and Z2 , the output of the heating member 20 is reduced again in matching with the rate of increase.

[0101] The output of the heating member 20 is variably controlled until the electrode temperature measured at the temperature measurement point remains constant. After the temperature of the electrode remains constant, the output of the heating member 20 remains constant to correspond to the temperature of the electrode. In this case, the output of the heating member 20 can be set to a constant output required to keep the electrode temperature constant.

[0102] Figure 8 is a graph showing a temperature stabilization process of an electrode according to an embodiment of the present invention; Fig. 9 is a graph showing output variation and the effect of shortening the temperature stabilization time according to one embodiment of the present invention.

[0103] Reference Figure 8 and Fig. 9It can be seen that according to the present invention, when the electrode starts to be driven, the electrode temperature stabilization time is greatly shortened.

[0104] Figure 8 The output variation of the heating element 20 shown by the dashed line is Figure 7 The output change of the heating member 20 shown in the dashed line corresponds to the output change of the heating member 20 and is a simplified Figure 7 The result of the change in the output of the heating member 20. Figure 8 In the embodiment, the initial output P1 of the heating member 20 is set to be high so that the temperature of the lower electrode can be increased quickly. Figure 7 The output of the heating member 20 is reduced to P2 as the electrode temperature increases. Unlike the prior art, the electrode temperature can be prevented from being excessively increased due to the heating of the high-output heating member by appropriately reducing the output of the heating member 20. That is, in this case, the output of the heating member 20 can be reduced within a range where the electrode temperature does not increase excessively, so that the rate of decrease of the output of the heating member has a slope proportional to the rate of increase of the electrode temperature.

[0105] Next, in Figure 7 In response to the decrease in electrode temperature, the output of the heating member 20 is increased to P3. Therefore, the electrode temperature is prevented from decreasing and the electrode temperature is brought close to the set target temperature. In this case, the rate of increase of the output can be appropriately determined within a range that allows the electrode temperature to approach the target temperature.

[0106] Thereafter, when the temperature of the electrode increases again, the output of the heating member 20 is slowly reduced to P4. In this case, the reduction rate of the output of the heating member 20 is determined to be within a range in which the target temperature of the electrode 1 is kept constant. That is, the reduction rate of the output of the heating member 20 can be set by considering the factors that the electrode temperature increases again due to the additional heating zones Z1 and Z and the factors that the electrode temperature decreases due to the reduction in the output of the heating member 20, so that the overall temperature of the electrode can be maintained equal to the target temperature.

[0107] Finally, when the electrode temperature is kept constant, the low output of the heating member 20 corresponding to the electrode temperature is kept constant.

[0108] Fig. 9 (a) only illustrates the output of the heating member 20 according to Figure 8 The drying time varies with the running time of the drying device.

[0109] Fig. 9 (b) illustrates the effect of shortening the temperature stabilization time by the method of variably controlling the output according to the present invention, compared with the method of controlling the output in proportion to the driving speed according to the related art.

[0110] like Figure 8 and Fig. 9 As shown, the time required to stably reach the target temperature is t1 (target time), which is much shorter than the stabilization time in the prior art. For example, it has been confirmed that when the control is performed according to the present invention, the stabilization time is shortened to 50% or more of the stabilization time of the prior art. Since the electrode installed in the heating chamber is repeatedly driven and stopped, the stabilization time is shortened as described above when the device is operated once, and when the total number of operations per day, week or month is taken into account, the operation productivity according to the present invention can be significantly improved. In addition, the number of electrodes 1 produced within an unstable temperature range is greatly reduced, so the quality stability of the electrode 1 is significantly improved.

[0111] In addition, if Figure 4 As shown, the controller 30 of the electrode drying device 100 can determine whether to turn on or off the device or the electrode drying device 100. For example, the driving of the electrode can be started by sending an operation signal to the driving components (especially, motors, etc.) of the unwinder and rewinder that are in a stopped state before driving the electrode. In response to starting to drive the electrode, a heating instruction can be issued to the heating zones Z1, Z2 and Z3 in the heating chamber, especially the heating member 20 at the last heating zone Z3. For example, a start signal can be sent to the infrared lamp 21 of the heating member 20. In addition, during the operation of the electrode drying device 100, the controller 30 can stop the electrode drying device 100 for a specific reason (equipment failure, the electrode is dried to a desired level, etc.). That is, the driving components of the unwinder and rewinder can be turned off and a shutdown signal can be sent to the infrared lamp 21.

[0112] In addition, the controller 30 can adjust the driving speed of the electrode by adjusting the rotation speed of the driving component (e.g., a motor). The controller 30 can also control the acceleration of the electrode until the target driving speed is reached, and whether the electrode is driven at a constant speed after the target driving speed is reached. In addition, the controller 30 can also control the output of the heating member 20. For example, when the heating member 20 is a hot air blowing device, the output of the heating member 20 can be adjusted by adjusting the revolutions per minute (RPM) of the hair dryer, the dry air temperature, etc. When the heating member 20 includes an infrared lamp 21, the output of the heating member 20 can be adjusted by controlling the amount of infrared rays emitted to the electrode.

[0113] The present invention also provides a method of drying an electrode which is initially driven in a stationary state in a heating chamber.

[0114] In the electrode drying method, the output of the heating member 20 at the last heating zone Z3 in the heating chamber is variably controlled in response to the temperature change of the electrode measured between the last heating zone Z3 and the electrode outlet 11b of the heating chamber according to the operation time of the electrode drying device 100.

[0115] Specifically, when the measured temperature of the electrode changes, the temperature change of the electrode may be corrected by reducing or increasing the output of the heating member 20 inversely to the change in the electrode temperature.

[0116] For example, when the measured temperature of the electrode increases according to the time required to pass through the last heating zone Z3, or increases as the electrode passes through the additional heating zone Z2 before the last heating zone Z and the last heating zone Z3, the output of the heating member 20 may be controlled by at least one of the following:

[0117] i) reducing the output of the heating member 20 in proportion to the rate of increase in the electrode temperature to prevent the electrode temperature from excessively increasing; and

[0118] ii) The output of the heating member 20 is reduced in proportion to the rate of increase of the electrode temperature to maintain the target temperature of the electrode.

[0119] In addition, in the method of drying the electrode, since the time required for the electrode to pass through the last heating zone Z3 becomes relatively shorter when the electrode passes through the non-heating section NH before the last heating zone Z, and / or since the driving speed of the electrode increases, when the measured temperature of the electrode decreases, the output of the heating member 20 can be increased in proportion to the rate of decrease in the temperature of the electrode to make the temperature of the electrode close to the target temperature.

[0120] In the electrode drying method of the present invention, the output of the heating member 20 may be changed until the measured temperature of the electrode is kept constant, and kept constant after the electrode temperature is kept constant.

[0121] Fig.10 is a flow chart of an electrode drying method according to one embodiment of the present invention.

[0122] For example, when Figure 7 The electrode temperature at the temperature measurement point shown is due to Figure 4 When the high power applied when the electrode starts to be driven in the electrode drying device 100 changes, the output of the heating member 20 at the last heating zone Z3 is as follows Fig.11 Changes as shown.

[0123] Specifically, in operation S10, since the initial temperature of the electrode is low, a relatively high power is applied to the electrode to quickly increase the temperature of the electrode.

[0124] In operation S20, the output of the heating member 20 is reduced to 0.1% in response to the change in the electrode temperature at the temperature measurement point according to the time required to pass through the last heating zone Z3. Figure 8Basically, the rate of decrease in output is proportional to the rate of increase in electrode temperature, but the rate of decrease in output and the point in time at which the output decrease ends can be appropriately determined to prevent the electrode temperature from excessively increasing at the point in time at which the output decrease will end.

[0125] In operation S30, in response to a decrease in the electrode temperature and an increase in the electrode driving speed when the electrode passes through the non-heating section NH, the output of the heating member 20 is increased to Figure 8 Basically, the rate of increase of the output is proportional to the rate of decrease of the electrode temperature, but the rate of increase of the output and the time point at which the output increase ends can be appropriately determined so that the temperature of the electrode can approach the target temperature at the time point at which the output increase ends.

[0126] In operation S40, when the electrode passes through the additional heating zone Z2 and the last heating zone Z3, in response to the electrode temperature rising again, the output of the heating member 20 is gradually reduced to P4. In this case, the reduction rate of the output of the heating member 20 and the time point when the output reduction ends are determined to be within the range of maintaining the electrode target temperature.

[0127] Finally, in operation S50, when the electrode temperature does not increase and remains constant, the output of the heating member 20 is maintained low.

[0128] (Second Embodiment)

[0129] In the electrode drying device 100 and the electrode drying method of the first embodiment, when the heating member 20 with a fixed output (e.g., high output) is applied, the output of the heating member 20 is variably controlled to compensate for the inevitable change in the initial temperature of the electrode due to the position of the electrode in the heating chamber and the arrangement of the heating zones Z1, Z2, and Z3. Therefore, as described above, the time required for the temperature of the electrode near the electrode outlet 11b to stabilize may be significantly reduced.

[0130] However, the time required until the electrode temperature stabilizes inevitably varies depending on the initial state of the electrode before driving the electrode or the target driving speed of the electrode.

[0131] Fig.11 is a graph showing the initial temperature of the electrode and the change in the electrode temperature according to the output.

[0132] During the continuous operation of the apparatus or electrode drying device 100, the temperature of the stopped electrode is high when the temporarily stopped apparatus is restarted, for example, due to the residual heat of the infrared lamp 21 and the internal temperature of the heating chamber. Fig.11 (a) illustrates a case where the output of the heating member 20 is controlled to be constant when the electrode initial temperature measured at the above-mentioned temperature measurement point changes.

[0133] When the initial temperature of the electrode is high, the electrode temperature becomes too high even when the heating member 20 having the same initial output is applied. When the initial temperature of the electrode is low, the heating time increases when the heating member 20 having the same initial output is applied. Fig.11 As shown in (b), the electrode temperature stabilization time deviates.

[0134] Therefore, in order to prevent the electrode temperature from excessively rising, the heating time from being prolonged, and to reduce the deviation of the electrode stable temperature, the controller 30 may set the initial output of the heating member 20 to be inversely proportional to the electrode temperature.

[0135] Reference Fig.12 (a), when the initial temperature of the electrode is low, the initial output of the heating member 20 is set to be high; when the initial temperature of the electrode is high, the initial output of the heating member 20 is set to be low in inverse proportion to the initial temperature of the electrode. The initial temperature of the electrode should be understood as the initial temperature of the electrode measured at the temperature measurement point in the heating chamber before starting to drive the electrode. The initial output of the heating member 20 should be understood as the initial output of the heating member 20 at the time point when starting to drive the electrode.

[0136] In addition, in the present embodiment, setting the initial output to be inversely proportional to the initial temperature of the electrode should not be understood as variably controlling the output of the heating member 20 according to the operating time of the electrode drying device 100 as in the first embodiment. Setting the initial output to be inversely proportional to the initial temperature of the electrode should be understood as setting the initial output to be higher when the initial temperature of the electrode is lower, and setting the initial output to be lower (proportional to the initial temperature) when the initial temperature of the electrode is higher. That is, the initial output of the heating member 20 is determined in consideration of the initial state of the electrode in the heating chamber. Therefore, in order to variably control the output after setting the initial output, the linear speed proportional control method of the prior art or the variable control method performed in response to temperature changes according to the first embodiment can be adopted. However, when the variable control method of the first embodiment is selected, the time required to reach electrode temperature stabilization is reduced, and the deviation of the temperature stabilization time is also reduced, as described below.

[0137] Fig.12 (b) illustrates that when the initial temperature of the electrode is high or low, when the output of the heating member 20 is set in inverse proportion to the initial temperature of the electrode, the deviation of the electrode temperature stabilization time is reduced.

[0138] (Third Embodiment)

[0139] Depending on the target driving speed of the electrode driven in the heating chamber, the electrode temperature stabilization time inevitably deviates.

[0140] Fig.13 is a graph showing a change in electrode temperature according to a target driving speed of the electrode and an output of a heating member.

[0141] like Fig.13 As shown in (b), when the target driving speed of the electrode is high, the electrode cannot be sufficiently heated, so when the electrode reaches the electrode outlet 11b, the heating time of the electrode increases. On the other hand, when the target driving speed of the electrode is low, the electrode may be overheated, so the electrode temperature may be too high. Therefore, Fig.11 As shown in (b), the electrode temperature stabilization time will deviate.

[0142] Therefore, in order to prevent the electrode temperature from excessively rising, the heating time from being prolonged, and to reduce the deviation of the electrode stable temperature, the controller 30 may set the initial output of the heating member 20 to be proportional to the target driving speed.

[0143] Fig.14 is a graph showing an initial output control principle according to another embodiment of the present invention.

[0144] Reference Fig.14 (a), when the target driving speed is low, the initial output of the heating member 20 is set to be low, and when the target driving speed is high, the initial output of the heating member 20 is set to be high in inverse proportion to the target driving speed.

[0145] It should be understood that when the target driving speed is high, the initial driving speed of the electrode (i.e., the speed acceleration ratio) is high. Therefore, in the initial acceleration section of the electrode, the electrode is driven at a relatively high speed. Therefore, the electrode is driven without being fully heated, and the heating time of the electrode at the temperature measurement point is increased.

[0146] On the contrary, it should be understood that when the target driving speed is low, the initial driving speed of the electrode (i.e., the speed acceleration ratio) is also low. Therefore, in the initial acceleration section of the electrode, the electrode is driven at a relatively low speed. Therefore, the electrode may be overheated, and the electrode temperature at the temperature measurement point may be too high.

[0147] Similarly, in the second embodiment, in order to variably control the output after setting the initial output (first output) of the heating member 20, the linear speed proportional control method in the prior art or the variable control method performed in response to temperature changes of the first embodiment can be adopted. However, when the variable control method of the first embodiment is selected, the time required to achieve electrode temperature stabilization is reduced, and the deviation of the temperature stabilization time is also reduced, as described below.

[0148] Fig.14(b) illustrates that when the target driving speed is higher or lower, when the output of the heating member 20 is set to be proportional to the target driving speed of the electrode, the deviation of the electrode temperature stabilization time is reduced.

[0149] As described above, according to the present invention, the time required for the electrode temperature to stabilize can be significantly reduced. Therefore, the operating productivity of the electrode drying process and the quality stability of the electrode can be significantly improved.

[0150] According to one embodiment of the present invention, by setting the initial output of the heating member 20 (especially, the initial output of the heating member 20 at the last heating zone Z3) in response to the initial temperature of the electrode and the target driving speed, the deviation in the time required to reach electrode temperature stabilization can be reduced.

[0151] The electrode drying device 100 and the electrode drying method of the present invention described above are applicable not only to the drying process after the electrode coating process but also to sub-processes performed until the electrode is housed in a battery case and to sub-processes requiring the electrode to be dried.

[0152] The above description is merely an example of the technical concept of the present invention, and various modifications and changes may be made by those skilled in the art without departing from the essential features of the present invention.

[0153] Therefore, the drawings of the present invention described herein are not used to limit the technical concept of the present invention, but to describe the technical concept, and the scope of the technical concept of the present invention is not limited by the drawings. The protection scope of the present invention should be interpreted based on the attached claims, and all technical concepts within the same scope as the present invention should be interpreted as included within the scope of the present invention.

[0154] (reference numerals)

[0155] 1: Electrode

[0156] 10: Heating chamber

[0157] 11: Room wall (room frame)

[0158] 11a: Electrode inlet

[0159] 11b: Electrode outlet

[0160] 20: Heating component

[0161] 21: Infrared light

[0162] 22: Support frame

[0163] 30: Controller

[0164] R: Guide roller

[0165] Z1: First heating zone

[0166] Z2: Second heating zone

[0167] Z3: The third heating zone (the last heating zone)

[0168] NH: Non-heating section

[0169] S: Temperature measuring component (temperature sensor)

Claims

1. An electrode drying device, comprising: a heating chamber having an electrode inlet and an electrode outlet, wherein an electrode is mounted to be driven between the electrode inlet and the electrode outlet; a heating member installed in the heating chamber to heat the electrode at a last heating zone before the electrode exit; and A controller is configured to variably control the output of the heating member in response to a change in the temperature of the electrode measured between the last heating zone and the electrode outlet according to an operation time of the electrode drying device.

2. The electrode drying device according to claim 1, wherein: The electrode is installed in the heating chamber so that a driving direction of the electrode is changed at least once.

3. The electrode drying device according to claim 1, wherein: When the electrode stops in the heating chamber, the electrode is accelerated at a specific rate until a target driving speed is reached.

4. The electrode drying device according to claim 2, wherein: A plurality of heating zones are provided in the heating chamber, each heating zone corresponds to one of the driving directions of the electrode, and The final heating zone is the rearmost heating zone among the plurality of heating zones.

5. The electrode drying device according to claim 1, wherein: The controller corrects the temperature of the electrode by increasing or decreasing the output of the heating member inversely to changes in the measured temperature of the electrode.

6. The electrode drying device according to claim 5, wherein: The controller varies the output of the heating member until the measured temperature of the electrode remains constant, and The resulting output of the heating member is maintained constant to correspond to the temperature of the electrode after the temperature of the electrode is maintained constant.

7. The electrode drying device according to claim 5, wherein: When the measured temperature of the electrode increases, the output of the heating member is controlled by at least one of the following means: i) reducing the output of the heating member in proportion to the rate of increase in the temperature of the electrode to prevent the temperature of the electrode from excessively increasing; and ii) reducing the output of the heating member in proportion to the rate of increase in the temperature of the electrode to maintain the target temperature of the electrode.

8. The electrode drying device according to claim 5, wherein: When the measured temperature of the electrode decreases, the output of the heating member is increased in proportion to the rate of decrease in the temperature of the electrode so that the temperature of the electrode approaches a target temperature.

9. The electrode drying device according to claim 1, wherein: The controller sets an initial output of the heating member to be inversely proportional to an initial temperature of the electrode measured between the last heating zone and the electrode outlet.

10. The electrode drying device according to claim 1, wherein: The controller sets an initial output of the heating member in proportion to a target driving speed of the electrode.

11. A method for drying an electrode which is initially driven in a stationary state in a heating chamber, the method comprising the steps of: The output of the heating member at the last heating zone is variably controlled in response to a change in the temperature of the electrode measured between the last heating zone in the heating chamber and the electrode outlet of the heating chamber according to the operation time of the electrode drying device.

12. The method according to claim 11, wherein: When the measured temperature of the electrode changes, the temperature change of the electrode is corrected by reducing or increasing the output of the heating member inversely to the temperature change of the electrode.

13. The method according to claim 12, wherein: varying the output of the heating member until the measured temperature of the electrode remains constant, and The resulting output of the heating member is maintained constant to correspond to the temperature of the electrode after the temperature of the electrode is maintained constant.

14. The method according to claim 11, wherein: The initial output of the heating means is arranged to be inversely proportional to the initial temperature of the electrode measured between the last heating zone and the electrode outlet.

15. The method according to claim 11, wherein: An initial output of the heating member is set proportional to a target drive speed of the electrode measured between the last heating zone and the electrode outlet.

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