Electrode drying system and electrode drying method

Abstract

The present invention provides an electrode drying system and an electrode drying method, wherein the position of a first drying zone in which a to-be-dried electrode in a constant rate section state moves is determined on the basis of an electrode surface temperature, and the adjustment of the number of first drying zones and heat compensation in a drying zone around the first drying zone can be automatically performed in accordance with the desired adhesiveness and drying rate of the electrode to be dried.

Description

Electrode drying system and electrode drying method

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

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0146755, filed October 30, 2023, the entire contents of which are incorporated herein by reference.

[0003] As technological developments and demand for mobile devices increase, the demand for rechargeable, miniaturized, and high-capacity secondary batteries is rapidly increasing. Furthermore, lithium secondary batteries, boasting high energy density and voltage, are commercialized and widely used.

[0004] Lithium secondary batteries are structured to have an electrode assembly with a porous separator interposed between a positive electrode and a negative electrode, each of which has an active material coated on a current collector, and an electrolyte containing a lithium salt impregnated therein. The electrode is manufactured by coating a slurry containing an active material, a binder, and a conductive agent dispersed in a solvent onto a current collector, followed by drying and pressing.

[0005] Typically, the adhesive strength between the current collector and the slurry is determined during the drying process. This adhesive strength is a key quality factor for preventing thermal wrinkling of the electrode.

[0006] The drying process is performed by sequentially passing the electrode to be dried through a plurality of drying zones arranged along one direction.

[0007] In order to increase the above adhesive strength, the constant rate section in which the surface temperature of the electrode is maintained constant must be designed to be long to minimize migration of the binder during the drying process.

[0008] Specifically, among multiple drying zones, the drying zones in which the surface temperature of the electrode is maintained constant were identified as constant rate zones, and then the drying temperature of the corresponding drying zones was lowered to design the constant rate zone longer.

[0009] Up to now, the only way to determine the dry zone corresponding to the constant rate section was to visually check with the user whether the drying electrode surface changed from a glossy surface to a matte surface. This method had the problem of being cumbersome for the user to visually check every time and of low accuracy because the results varied for each user.

[0010] The present invention, unlike the existing drying method that visually determines the constant rate section, determines the position of the first drying zone in which the electrode to be dried moves based on the electrode surface temperature, and automatically adjusts the number of the first drying zones and compensates for the amount of heat in the drying zones around the first drying zone by adjusting the adhesive strength and drying rate of the electrode to be dried. It is an object of the present invention to provide an electrode drying system and an electrode drying method.

[0011] In order to solve the above problem, according to one embodiment of the present invention, an electrode drying system is provided, including a plurality of drying zones each including a drying space in which an electrode to be dried is dried and a heat supply unit provided to supply a preset amount of heat to the drying space, which are arranged along one direction, a moving unit for sequentially moving the electrode to be dried through the plurality of drying zones, a plurality of temperature sensors provided in each of the plurality of drying zones and for measuring a surface temperature of the electrode to be dried in each of the drying zones, a determining unit for determining a plurality of first drying zones to which the electrode to be dried moves in a constant rate state (T state) in which a change in the surface temperature is maintained below a predetermined value based on the surface temperature of the electrode to be dried measured by the plurality of temperature sensors, and a first controlling unit provided to control the amount of heat supplied from the heat supply unit in each of the first drying zones in order to increase or decrease the number of the first drying zones determined by the determining unit.

[0012] Additionally, the judgment unit may determine at least one drying zone located behind the second drying zone having the highest electrode surface temperature among the plurality of drying zones as the first drying zone.

[0013] Additionally, the difference (T2-T1) between the electrode surface temperature (T2) of the second drying zone and the electrode surface temperature (T1) of the first drying zone may be 5°C or less.

[0014] In addition, the first control unit can control the heat supply amount of each first drying zone to a first heat supply amount (A) lower than the preset heat supply amount in order to increase the number of first drying zones determined by the determination unit.

[0015] In addition, based on the first heat supply amount (A), a second control unit may be included that controls the heat supply amount of at least one third drying zone located in front of the first drying zone and the heat supply amount of at least one fourth drying zone located behind the first drying zone to be higher than the preset heat supply amount.

[0016] In addition, the second control unit can control the heat supply of the third drying zone to a second heat supply (B) that is 25% to 50% higher than the first heat supply than the preset heat supply, and can control the heat supply of the fourth drying zone to a third heat supply (C) that is 25% to 50% higher than the first heat supply (A) than the preset heat supply.

[0017] In addition, the second control unit can adjust the heat supply of the third drying zone and the heat supply of the fourth drying zone to be higher than the preset heat supply, respectively, based on the difference between the drying rate (D1) of the drying target electrode that has been sequentially dried through a plurality of drying zones and the preset target drying rate (D0).

[0018] In addition, the second control unit can control the heat supply of the third drying zone and the heat supply of the fourth drying zone to be higher than the preset heat supply until the difference between the drying rate (D1) of the drying target electrode and the preset target drying rate (D0) is controlled within the allowable error range.

[0019] Additionally, the electrode to be dried may be a cathode including a current collector and a cathode slurry layer provided on the current collector.

[0020] According to another embodiment of the present application, there is provided an electrode drying method using the electrode drying system described above, comprising: a determination step of determining a plurality of first drying zones in which an electrode to be dried moves to a constant rate state (T state) in which a change in surface temperature is maintained below a predetermined value among a plurality of drying zones; and a first adjustment step of adjusting the amount of heat supplied from a heat supply unit in each of the first drying zones to increase or decrease the number of first drying zones determined in the determination step.

[0021] Additionally, in the above method, the determination step may determine at least one drying zone located behind the second drying zone having the highest electrode surface temperature among the plurality of drying zones (100) as the first drying zone.

[0022] Additionally, in the above method, the difference (T2-T1) between the electrode surface temperature (T2) of the second drying zone and the electrode surface temperature (T1) of the first drying zone may be 5°C or less.

[0023] In addition, in the above method, the first adjustment step can adjust the heat supply amount of each first drying zone to a first heat supply amount (A) lower than the preset heat supply amount in order to increase the number of first drying zones determined in the determination step.

[0024] In addition, in the above method, a second adjustment step may be included, in which the heat supply amount of at least one third drying zone located in front of the first drying zone and the heat supply amount (C) of at least one fourth drying zone located behind the first drying zone are adjusted to be higher than the preset heat supply amount, based on the first heat supply amount (A).

[0025] The electrode drying system according to the present application determines the location of the first drying zone in which the electrode to be dried, which is in a constant rate zone state, moves based on the electrode surface temperature, and automatically adjusts the number of the first drying zones and compensates for the amount of heat in the drying zones around the first drying zone by adjusting the adhesive strength and drying rate of the electrode to be dried to the desired degree, thereby having the advantages of excellent drying quality of the electrode, efficiency of the drying process, and productivity of the drying process.

[0026] Figure 1 is a configuration diagram of an electrode drying system according to an embodiment of the present invention.

[0027] Hereinafter, an electrode drying system according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

[0028] In addition, regardless of the drawing symbol, identical or corresponding components are given identical or similar reference numbers and redundant descriptions thereof are omitted, and for the convenience of explanation, the size and shape of each component depicted may be exaggerated or reduced.

[0029] Figure 1 is a configuration diagram of an electrode drying system (1) according to an embodiment of the present invention.

[0030] Referring to FIG. 1, the electrode drying system (1) includes a plurality of drying zones (100), a moving part (200), a plurality of temperature sensors (300), a judgment part (400), and a first control part (500).

[0031] The above-described plurality of drying zones (100) are arranged along one direction and each includes a drying space (110) in which a drying target electrode (10) is dried and a heat supply unit (120) provided to provide a preset amount of heat to the drying space (110). The one direction may be the direction of movement of the moving unit (200).

[0032] In this document, 'one direction' refers to the driving direction (M) in which the target electrode (10) passes through multiple drying zones (100) or the movement path of the moving part (200).

[0033] The above-described plurality of drying zones (100) may include a chamber (or drying room) that provides a drying space (110) through which the electrodes to be dried may pass. The chamber may further include an air supply fan that forms an air supply flow from the outside, an exhaust fan that forms an exhaust flow from inside the chamber, and a circulation fan that forms a circulation flow inside the chamber. The chambers may be arranged at predetermined intervals along one direction on the movement path (M) of the moving part (200).

[0034] The above-mentioned plurality of drying zones (100) may be, for example, 10 or more, 20 or more, 30 or more, and preferably 10.

[0035] The above-described moving unit (200) moves the electrode to be dried (10) so as to be dried sequentially through a plurality of drying zones (100). The moving unit (200) can move the electrode to be dried (10) along one direction (M). The moving unit (200) can intermittently stop moving so that the electrode to be dried stays within the plurality of drying zones (100) for a certain period of time, or can move the electrode to be dried through the drying zones at a slow speed. For example, the moving unit (200) can include a plurality of transport rolls, and can be configured in a roll-to-roll manner in which the plurality of transport rolls continuously transport the electrode to be dried (10).

[0036] The above-described electrode (10) to be dried may be a slurry in which an active material, a binder, and a conductive material are dispersed in a solvent applied onto a current collector (or an electrode sheet), and the application may be performed by coating or rolling. If the electrode to be dried is a positive electrode, the positive electrode slurry may be coated or rolled onto a positive electrode current collector (positive electrode sheet), and if the electrode to be dried is a negative electrode, the negative electrode slurry may be coated or rolled onto a negative electrode current collector (negative electrode sheet). The positive and negative electrode slurries may each have an active material, a binder, and a conductive material dispersed in a solvent.

[0037] The drying rate of the above-mentioned drying target electrode (10) may increase as it passes through multiple drying zones. For example, if the drying target electrode exhibits a drying rate of 1% or less when moving through the first drying zone it first enters, it may exhibit a drying rate of 1% or more when moving through the second drying zone located after the first drying zone.

[0038] The plurality of temperature sensors (300) are respectively provided in the plurality of drying zones (100) and can measure the surface temperature of the electrodes (10) to be dried within each drying zone. The plurality of temperature sensors (300) can measure the surface temperature of the electrodes (10) moving through the drying zones in which they are respectively installed in real time. For example, the temperature sensor may be an infrared thermometer, but is not limited thereto, and various known devices capable of measuring the surface temperature of the electrodes may be used.

[0039] The above-described judgment unit (400) determines a plurality of first drying zones (101) in which the drying target electrode moves to a constant-rate state (T state) in which the change in surface temperature is maintained below a predetermined value among the plurality of drying zones (100), based on the surface temperature of the drying target electrode (10) measured by the plurality of temperature sensors (300). For example, the drying target electrode in the constant-rate state may have a temperature change of 0.1°C or less, 0.5°C or less, or 1°C or less within the corresponding drying zone.

[0040] In the past, the constant rate state of the drying target electrode had to be determined visually each time, whereas the present invention can increase the accuracy of determining the constant rate section by determining the drying zone in which the constant rate drying target electrode moves based on the surface temperature of the electrode.

[0041] Specifically, the electrode drying process can be composed of a preheating section (a section in which the temperature rises while the moisture content decreases slightly), a constant rate section (a section in which the temperature remains constant while the moisture content decreases significantly), and a deceleration section (a section in which the temperature rises while the moisture content decreases slightly).

[0042] In the section where the functional content is greatly reduced, the binder moves significantly to the surface of the electrode coating layer (slurry layer), so the binder migration phenomenon occurs in the constant rate section.

[0043] At this time, as the constant rate drying time increases, the binder movement speed decreases, and as the constant rate drying speed increases, the binder movement speed increases. That is, when the preheating section in electrode drying is shortened, the constant rate drying time relatively increases, and as a result, the binder movement phenomenon can be reduced.

[0044] The number of first drying zones (101) determined by the above-described judgment unit (400) may be at least two, three, or four. The length of the constant rate section may be determined depending on the number of first drying zones (101). For example, if the number of first drying zones (101) increases, the constant rate section may increase, and if the number of first drying zones (101) decreases, the constant rate section may shorten.

[0045] A drying target electrode (10) that sequentially passes through a plurality of drying zones can sequentially reach a preheating zone, a constant rate zone, and a deceleration zone. For example, there may be at least one drying zone corresponding to a preheating zone in front of a first drying zone (101), and there may be at least one drying zone corresponding to a deceleration zone behind the first drying zone (101).

[0046] The first control unit (500) is provided to control the amount of heat supplied from the heat supply unit (120) in each first drying zone (101) in order to increase or decrease the number of first drying zones (101) determined by the determination unit (400). The first control unit (500) can control the adhesive strength of the electrode to be dried by increasing or decreasing the number of first drying zones (101). For example, as the number of first drying zones (101) increases, the constant rate section becomes longer, and the adhesive strength of the electrode to be dried is controlled to be high, and as the number of first drying zones (101) decreases, the constant rate section becomes shorter, and the adhesive strength of the electrode to be dried is controlled to be low.

[0047] In the present invention, the adhesive strength of the electrode to be dried means the adhesive strength between the current collector and the slurry in the electrode to be dried.

[0048] Unlike the existing manual method of visually determining the surface temperature of an electrode to be dried, the electrode drying system according to the present invention determines the first drying zone (101) based on the surface temperature of the electrode to be dried, and the processes of controlling the number of first drying zones (101) are automatically performed through an algorithm.

[0049] In one example, the judgment unit (400) may determine at least one drying zone located behind the second drying zone (102) having the highest electrode surface temperature among the plurality of drying zones (100) as the first drying zone (101).

[0050] In the present invention, the 'front' and 'back' of the first drying zone (101) may indicate relative positions based on the entry portion (S) of the electrode to be dried. For example, when comparing the positions of two drying zones, a drying zone located close to the entry portion (S) of the electrode to be dried may be indicated as being relatively 'front' (also referred to as the 'upstream' side), and a drying zone located far from the entry portion (S) of the electrode to be dried may be indicated as being relatively 'back' (also referred to as the 'downstream' side).

[0051] In one specific example, the difference (T2-T1) between the electrode surface temperature (T2) of the second drying zone (102) and the electrode surface temperature (T1) of the first drying zone (101) may be 5°C or less. For example, the determination unit (400) may determine drying zones having a difference of 5°C or less from the electrode surface temperature of the second drying zone (102) as the first drying zone (101). When there are 10 drying zones, the second drying zone (102) may be the third or fourth drying zone.

[0052] More specifically, when the electrode surface temperature of the second drying zone (102) is 59°C, the judgment unit (400) can judge the drying zones located behind (downstream side) the second drying zone (102) and having an electrode surface temperature of 54°C or higher as the first drying zone (101).

[0053] The electrode surface temperature (T2) of the second drying zone (102) refers to the electrode surface temperature of the drying target electrode staying or moving within the second drying zone (102), and this can be measured by a temperature sensor (300) installed in the second drying zone (102). Similarly, the electrode surface temperature (T1) of the first drying zone refers to the electrode surface temperature of the drying target electrode staying or moving within the first drying zone (101), and this can be measured by a temperature sensor (300) installed in the first drying zone (120). In the present invention, for convenience, the symbols of the temperature sensors installed in different drying zones are indicated by the same symbol '300'.

[0054] The first control unit (500) can adjust the heat supply amount of each first drying zone (101) to a first heat supply amount (A) lower than the preset heat supply amount in order to increase the number of first drying zones (101) determined by the determination unit (400). Conversely, the first control unit (500) can adjust the heat supply amount of each first drying zone (101) to a first heat supply amount (A) higher than the preset heat supply amount in order to decrease the number of first drying zones (101) determined by the determination unit (400). The first control unit (500) can provide a drying target electrode having a desired adhesive strength by adjusting the heat supply amount of the first drying zone (101) to be higher or lower than the preset heat supply amount.

[0055] Meanwhile, if the heat supply of the first drying zone (101) is adjusted to a first heat supply (A) lower than the preset heat supply, the drying target electrode can exhibit a lower drying rate than when the heat supply is preset.

[0056] In other words, as the adhesive strength of the electrode to be dried increases, the drying rate may decrease. This decreased drying rate may be increased by heat compensation, which increases the heat supply to the drying zone around the first drying zone (101).

[0057] The electrode drying system according to the present application may include a second control unit (600) that controls the heat supply of at least one third drying zone (103) located in front (upstream side) of the first drying zone (101) and the heat supply of at least one fourth drying zone (104) located behind the first drying zone (101) to be higher than the preset heat supply amount, based on the first heat supply amount (A). The second control unit (600) may control the heat supply of at least one third drying zone (103) located in front of the first drying zone (101) and the heat supply of at least one fourth drying zone (104) located behind the first drying zone (101) to be higher than the preset heat supply amount, in order to compensate for the heat amount for the first heat supply amount (A).

[0058] The drying target electrode in the third drying zone (103) may be in a preheating zone state, and the drying target electrode in the fourth drying zone (104) may be in a deceleration zone state. The length of the preheating zone may be determined according to the number of third drying zones (103), and the length of the deceleration zone may be determined according to the number of fourth drying zones (104). For example, as the number of third drying zones (103) increases, the length of the preheating zone may become longer, and as the number of fourth drying zones (104) increases, the length of the deceleration zone may become longer. In addition, since the second drying zone (102) described above is located in front of the first drying zone (101), it may be included in the third drying zone (103).

[0059] In one specific example, the second control unit (600) can control the heat supply of the third drying zone (103) to a second heat supply (B) that is 25% to 50% higher than the first heat supply (A) than the preset heat supply, and can control the heat supply of the fourth drying zone (104) to a third heat supply (C) that is 25% to 50% higher than the first heat supply (A) than the preset heat supply.

[0060] For example, when the first heat supply amount (A) is lower by 'x' than the preset heat supply amount, the second heat supply amount (B) and the third heat supply amount (C) can be adjusted to be higher by 0.25 to 0.5 x than the preset heat supply amount, respectively.

[0061] The second heat supply (B) of the third drying zone (103) and the third heat supply (C) of the fourth drying zone (104) may be higher than the preset heat supply by 25%, 30%, 35%, 40%, 45% or 50% of the first heat supply (A), respectively.

[0062] The above heat supply unit (120) may include an infrared heater (121) that supplies radiant heat to the drying space (110), and a hot air blower (122) that supplies convection heat to the drying space (110).

[0063] The above infrared heater (121) may be a mid-infrared heater (121) or a near-infrared heater (121). Here, the mid-infrared heater (121) is a heater that emits mid-infrared rays with a wavelength of approximately 2 to 5 ㎛, and the near-infrared heater (121) means a heater that emits near-infrared rays with a wavelength of approximately 0.7 to 1.5 ㎛.

[0064] The above first control unit (500) can increase the number of first drying zones (101) by lowering the heat supply of the radiant heat of the infrared heater (121) and the convective heat of the hot air blower (122), and can provide heat compensation by increasing the heat supply of the radiant heat of the infrared heater (121) and the convective heat of the hot air blower (122) of other drying zones located in front and behind the first drying zone (101).

[0065] In the present invention, the amount of heat supply may include the amount of heat supply of radiant heat from the infrared heater (121) and the amount of heat supply of convection heat from the heat blower (122). The amount of heat supply of radiant heat is determined according to the temperature (℃) of the infrared heater (121), and the amount of heat supply of convection heat from the heat blower may be determined according to the fan speed (RPM).

[0066] For example, the first control unit (500) can lower the heat supply to the first drying zone (101) by adjusting the temperature of the infrared heater (121) to be lower than the preset temperature and by adjusting the fan speed (RPM) of the heat blower (122) to be lower than the preset speed. In addition, the second control unit (600) can increase the heat supply to the third and fourth drying zones (103, 104) by adjusting the temperature of the infrared heater (121) to be higher than the preset temperature and by adjusting the fan speed (RPM) of the heat blower (122) to be higher than the preset speed.

[0067] More specifically, the first control unit (500) lowers the temperature of the infrared heater (121) in the first drying zone (101) by 4°C below the preset temperature and lowers the speed of the fan of the heat blower (122) by 100 RPM below the preset speed, and the second control unit (600) raises the temperature of the infrared heater (121) in the third and fourth drying zones (103, 104) by 1 to 2°C above the preset temperature and raises the speed of the fan of the heat blower (122) in the third and fourth drying zones (103, 104) by 25 to 50 RPM above the preset speed, thereby performing heat compensation for the reduced heat supply in the first drying zone (101).

[0068] In one example, the first control unit (500) can control the number of first drying zones based on the target adhesive strength of the preset drying target electrode.

[0069] The first control unit (500) can increase the number of first drying zones (101) by controlling the heat supply in the first drying zone (101) to a first heat supply amount (A) lower than the preset heat supply amount when the adhesive strength of the drying target electrode that has been sequentially dried through a plurality of drying zones is lower than the target adhesive strength.

[0070] In another example, the second control unit (600) can adjust the heat supply amount (B) of the third drying zone (103) and the heat supply amount (C) of the fourth drying zone (104) to be higher than the preset heat supply amount, respectively, based on the difference between the drying rate (D1) of the drying target electrode that has been sequentially dried through a plurality of drying zones and the preset target drying rate (D0).

[0071] For example, the second control unit (600) can adjust the heat supply amount (B) of the third drying zone (103) and the heat supply amount (C) of the fourth drying zone (104) to be higher than the preset heat supply amount, respectively, until the difference between the drying rate (D1) of the electrode to be dried and the preset target drying rate (D0) is adjusted to be within the allowable error range. The second control unit (60) can repeatedly adjust the heat supply amount of the third drying zone (103) and the heat supply amount of the fourth drying zone (104) to be higher than the preset heat supply amount by 25 to 50% of the first heat supply amount (A) until the difference between the drying rate (D1) of the electrode to be dried and the preset target drying rate (D0) is adjusted to be within the allowable error range.

[0072] For example, the second control unit (600) can repeatedly increase the temperature of the infrared heater (121) and the fan speed of the hot air blower (122) in the third drying zone (103) and the fourth drying zone (104) to control the drying rate (D1) of the electrode to be dried within the allowable error range of the preset target drying rate (D0). The allowable error range may be within the range of ±1%.

[0073] The above target drying rate means a drying rate that prevents over-drying, under-drying, and heat wrinkles, and the electrode drying system according to the present invention can improve the quality of a product by adjusting the drying rate of the electrode to the target drying rate through heat compensation in the third drying zone (103) and the fourth drying zone (104) through the second controlling unit (600) while securing a desired adhesive strength through the first controlling unit (500).

[0074] In one specific example, the electrode to be dried may be a cathode comprising a current collector and a cathode slurry layer provided on the current collector. The cathode may be a coated cathode coated with a cathode slurry layer, or a rolled cathode formed by rolling the coated cathode.

[0075] The above negative electrode slurry may include a negative electrode active material, a binder, a conductive agent, and a dispersion medium.

[0076] The above-mentioned negative active material includes, for example, carbon-based active materials, silicon-based active materials, etc., and specifically, artificial graphite, natural graphite, hard carbon, soft carbon, graphitized carbon fiber, graphitized mesocarbon microbead, petroleum coke, resin sintered body, carbon fiber, pyrolytic carbon, Si, SiOx(0 <x≤2)로 표시되는 규소산화물, 리튬티타늄산화물(LTO), 리튬 금속, 또는 이들 중 2 이상을 포함할 수 있으나, 여기에 제한되지 않는다.

[0077] The above binder may be a variety of binder polymers, such as polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HEP), polyvinylidene fluoride, polyacrylonitrile, polymethylmethacrylate, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, styrene butylene rubber (SBR), fluoroelastomer, and various copolymers.

[0078] The above dispersion medium can be independently used as N-methylpyrrolidone, acetone, water, etc.

[0079] The conductive material is not particularly limited as long as it has conductivity and does not cause a chemical change in the battery, and examples thereof include carbon black such as carbon black, acetylene black, Ketjen black, channel black, paneth black, lamp black, and thermal black; conductive fibers such as carbon fibers or metal fibers; metal powders such as fluorocarbon, aluminum, and nickel powders; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0080] In a negative electrode having a constant rate section designed according to the drying system of the present invention, the binder is not distributed widely on the surface of the slurry layer but is located inside the active material layer, and the electrode contact between the current collector and the slurry layer is stable, so that the resistance characteristics are improved and the minimum adhesive force between the current collector and the slurry layer can be increased.

[0081]

[0082] The present application also relates to a method for drying an electrode. This drying method utilizes the aforementioned electrode drying system. Accordingly, any description that overlaps with the aforementioned description will be omitted below.

[0083] The above drying method includes a judgment step of judging a plurality of first drying zones (101) in which a drying target electrode moves to a constant rate state (T state) in which a change in surface temperature is maintained below a predetermined value among a plurality of drying zones (100), and a first adjustment step of adjusting the amount of heat supplied from a heat supply unit in each of the first drying zones (101) to increase or decrease the number of first drying zones (101) judged in the judgment step.

[0084] For example, the above judgment step may determine at least one drying zone located behind the second drying zone (102) having the highest electrode surface temperature among the plurality of drying zones (100) as the first drying zone (101).

[0085] Specifically, the difference (T2-T1) between the electrode surface temperature (T2) of the second drying zone (102) and the electrode surface temperature (T1) of the first drying zone (101) may be 5°C or less.

[0086] In one example, the first adjustment step may adjust the heat supply of each first drying zone to a first heat supply amount (A) lower than the preset heat supply amount in order to increase the number of first drying zones determined in the determination step.

[0087] In addition, the drying method may include a second adjustment step of adjusting the heat supply amount (B) of at least one third drying zone (103) located in front of the first drying zone (101) and the heat supply amount (C) of at least one fourth drying zone (104) located behind the first drying zone (101) to be higher than the preset heat supply amount, based on the first heat supply amount (A).

[0088] The second regulation step may be a heat compensation step that compensates for the heat supply reduced by the first regulation step.

[0089] In addition, the second control step may adjust the heat supply amount (B) of the third drying zone (103) and the heat supply amount (C) of the fourth drying zone (104) to be higher than the preset heat supply amount, respectively, based on the difference between the drying rate (D1) of the drying target electrode that has been sequentially dried through a plurality of drying zones (100) and the preset target drying rate (D0).

[0090] The preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and those skilled in the art having ordinary knowledge of the present invention will be able to make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be considered to fall within the scope of the following claims.

[0091] According to an electrode drying system related to one embodiment of the present invention, there are advantages in terms of excellent drying quality of the electrode, efficiency of the drying process, and productivity of the drying process.

Claims

1. A plurality of drying zones each including a drying space in which a drying target electrode is dried and a heat supply unit arranged to provide a preset amount of heat to the drying space, the drying zones being arranged along a direction of a work; A moving unit that moves a drying target electrode to be dried through a plurality of drying zones sequentially; A plurality of temperature sensors each provided in each of the above-described plurality of drying zones and measuring the surface temperature of a drying target electrode within each drying zone; A determination unit that determines a plurality of first drying zones in which the drying target electrode moves in a constant rate state in which the change in surface temperature is maintained below a predetermined value among the plurality of drying zones based on the surface temperature of the drying target electrode measured by the plurality of temperature sensors; and An electrode drying system, comprising a first control unit configured to control the amount of heat supplied from a heat supply unit within each first drying zone to increase or decrease the number of first drying zones determined by the above determination unit.

2. In paragraph 1, An electrode drying system, wherein the above judgment unit determines at least one drying zone located behind a second drying zone having the highest electrode surface temperature among a plurality of drying zones as a first drying zone.

3. In paragraph 2, An electrode drying system in which the difference (T2-T1) between the electrode surface temperature (T2) of the second drying zone and the electrode surface temperature (T1) of the first drying zone is 5°C or less.

4. In paragraph 1, An electrode drying system, wherein the first control unit controls the heat supply of each first drying zone to a first heat supply amount lower than a preset heat supply amount in order to increase the number of first drying zones determined by the determination unit.

5. In paragraph 4, An electrode drying system, comprising a second control unit that controls the heat supply of at least one third drying zone located in front of the first drying zone and the heat supply of at least one fourth drying zone located behind the first drying zone to be higher than the preset heat supply amount, based on the first heat supply amount.

6. In paragraph 5, An electrode drying system, wherein the second control unit controls the heat supply of the third drying zone to a second heat supply that is 25% to 50% higher than the first heat supply than the preset heat supply, and controls the heat supply of the fourth drying zone to a third heat supply that is 25% to 50% higher than the first heat supply than the preset heat supply.

7. In paragraph 5, An electrode drying system in which the second control unit sequentially controls the heat supply of the third drying zone and the heat supply of the fourth drying zone to be higher than the preset heat supply based on the difference between the drying rate of the electrode to be dried and the preset target drying rate after passing through a plurality of drying zones.

8. In paragraph 7, An electrode drying system in which the second control unit controls the heat supply of the third drying zone and the heat supply of the fourth drying zone to be higher than the preset heat supply until the difference between the drying rate of the electrode to be dried and the preset target drying rate is controlled within the allowable error range.

9. In paragraph 1, An electrode drying system, wherein the above-mentioned drying target electrode is a cathode including a current collector and a cathode slurry layer provided on the current collector.

10. An electrode drying method using an electrode drying system according to Article 1, A judgment step of determining a plurality of first drying zones in which a drying target electrode moves in a constant rate state in which a change in surface temperature among a plurality of drying zones is maintained below a predetermined value; and An electrode drying method, comprising a first adjustment step for adjusting the amount of heat supplied from a heat supply unit within each first drying zone to increase or decrease the number of first drying zones determined in the above judgment step.

11. In paragraph 10, An electrode drying method, wherein the above-described judgment step determines at least one drying zone located behind a second drying zone having the highest electrode surface temperature among a plurality of drying zones as a first drying zone.

12. An electrode drying method in claim 11, wherein the difference (T2-T1) between the electrode surface temperature (T2) of the second drying zone and the electrode surface temperature (T1) of the first drying zone is 5°C or less.

13. In paragraph 10, An electrode drying method in which the first adjustment step adjusts the heat supply of each first drying zone to a first heat supply amount lower than a preset heat supply amount in order to increase the number of first drying zones determined in the determination step.

14. In paragraph 13, An electrode drying method, comprising a second adjusting step of adjusting the heat supply of at least one third drying zone located in front of the first drying zone and the heat supply of at least one fourth drying zone located behind the first drying zone to be higher than the preset heat supply, based on the first heat supply amount.

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