Method for manufacturing electrode sheet
By detecting and controlling light irradiation based on real-time changes in liquid dispersion medium or temperature during the drying process, the method addresses overheating issues in electrode sheet manufacturing, ensuring high-quality electrode production.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
- Filing Date
- 2025-12-09
- Publication Date
- 2026-06-18
AI Technical Summary
Existing methods for drying coated sheets in electrode manufacturing, such as laser light irradiation, face challenges in detecting the timing of liquid dispersion medium depletion and temperature rise, leading to potential overheating and quality deterioration of the electrode sheets.
A method involving a transport step and a drying step that includes real-time detection of the remaining liquid dispersion medium or temperature changes during the drying process, allowing for controlled light irradiation termination points to prevent overheating and maintain sheet quality.
Prevents overheating and maintains the quality of electrode sheets by accurately controlling light irradiation based on detected remaining liquid dispersion medium or temperature changes, thereby ensuring consistent manufacturing outcomes.
Smart Images
Figure JP2025042876_18062026_PF_FP_ABST
Abstract
Description
Method for manufacturing an electrode sheet Cross-reference to related applications 【0001】 This disclosure claims the benefit of priority with respect to Japanese Patent Application No. 2024-214690, filed on December 9, 2024, with the Japan Patent Office, and the entire contents of the said patent application are incorporated herein by reference. 【0002】 This disclosure relates to a method for manufacturing an electrode sheet. 【0003】 Patent Document 1 proposes a “manufacturing method of an electrode sheet having a preparation step of preparing a coated sheet in which a coating part coated with an electrode material is disposed on a first surface of a current collector sheet having a longitudinal direction in a first direction, and a drying step of drying the coating part by irradiating the coated sheet with laser light while transporting the coated sheet in the first direction, wherein in the drying step, in a constant rate drying section and a falling rate drying section, the laser light of a pulse wave is irradiated.” 【0004】 Japanese Patent Application Laid-Open No. 2024-20798 【0005】 An electrode sheet used in the manufacture of a battery such as a lithium-ion secondary battery can be obtained by drying a coating film of a slurry containing an electrode material and a liquid dispersion medium while transporting a coated sheet having the coating film. As an example of a technique for drying a coated sheet, laser light irradiation can be mentioned. When laser light is continuously irradiated, the temperature of the coated sheet tends to become high, and the quality of the electrode may be affected. Although irradiation with laser light of a pulse wave has also been proposed, it has been difficult to detect the timing when the remaining amount of the liquid dispersion medium decreases and the temperature rapidly rises, and overheating is likely to occur. 【0006】 One aspect according to the present disclosure relates to a method for manufacturing an electrode sheet. The manufacturing method includes a transport step of transporting a coated sheet having a coating film of a slurry containing an electrode material and a liquid dispersion medium, and a first drying step of drying the coating film by irradiating the coated sheet with light in a drying line through which the coated sheet passes. The first drying step includes a remaining amount detection step of detecting the remaining amount of the liquid dispersion medium in the coating film when passing through the drying line, and a first irradiation control step of varying an end point of light irradiation of the drying line according to the detected remaining amount. 【0007】 Another aspect of this disclosure relates to a method for manufacturing an electrode sheet. The manufacturing method comprises a conveying step of conveying a coated sheet having a coating film of a slurry containing an electrode material and a liquid dispersion medium, and a second drying step of drying the coating film by irradiating the coated sheet with light in a drying line through which the coated sheet passes. The second drying step includes a temperature detection step of detecting the temperature of the coating film as it passes through the drying line, and a second irradiation control step of varying the light irradiation end point of the drying line according to the rate of change of the detected temperature. 【0008】 The method for manufacturing electrode sheets according to this disclosure makes it possible to prevent overheating during the drying process of the coated sheet and suppress deterioration of the quality of the electrode sheet. Novel features of the present invention are described in the appended claims, but the present invention, both in terms of its structure and content, along with other objects and features of the present invention, will be better understood by the following detailed description in conjunction with the drawings. 【0009】 This is an explanatory diagram illustrating a manufacturing line 100 used in a method for manufacturing an electrode sheet according to one embodiment of the present disclosure. This is a schematic graph showing the temporal change in the surface temperature of the coating film during continuous irradiation with laser light. This is a schematic graph showing the temporal change in the surface temperature of the coating film during intermittent irradiation with laser light. This is a schematic graph showing the relationship between the number of intermittent laser light irradiations and the heating / cooling rate. This is a graph illustrating experimental data of the surface temperature and temperature change rate of the coating film during intermittent laser light irradiation. This is a graph illustrating the average temperature rise rate for 0.1 seconds after heating by each irradiation in Figure 5. This is a graph illustrating experimental data of the temporal change in the surface temperature of the coating film according to the length of laser light irradiation time. This is a graph illustrating experimental data similar to that in Figure 7, but limited to after laser light irradiation. This is a distribution diagram showing the relationship between dry-weight moisture content and heating rate. This is a distribution diagram showing the relationship between dry-weight moisture content and cooling rate. 【0010】The method for manufacturing an electrode sheet according to this disclosure will be described below with examples. However, this disclosure is not limited to the examples described below. In the following description, specific numerical values and materials may be given as examples, but other numerical values and materials may be applied as long as the effects of this disclosure are obtained. 【0011】 1. Method for Manufacturing an Electrode Sheet (1) The method for manufacturing an electrode sheet (1) comprises a transport step and a first drying step, as described below. In this manufacturing method, a coated sheet having a coating film of a slurry containing electrode material and liquid dispersion medium is transported on a drying line, and the coating film is dried by light irradiation. The temperature of the coating film is detected during the transport of the coated sheet, and the remaining amount of liquid dispersion medium is estimated from the rate of change of the detected temperature to control the light irradiation. 【0012】 1.1 Conveying Process In the conveying process, coated sheets having a coating film of slurry containing electrode material and liquid dispersion medium are conveyed. Conveying is performed, for example, by a roll-to-roll method, but is not limited to this method. 【0013】 In the roll-to-roll method, conveyance takes place along a transport path between the unwinding roll and the unwinding roll. The transport path typically runs along the entire or a portion of the electrode sheet manufacturing line. In the manufacturing line, the wound core sheet is supplied from the unwinding roll, and a slurry is applied to the core sheet by a coating device located upstream of the transport path, resulting in a coated sheet. The coated sheet then undergoes drying, rolling, and other processes to become an electrode sheet. The drying process is carried out on a drying line. The drying line can also be referred to as a drying device. 【0014】 The slurry is prepared by mixing the electrode material with a liquid dispersion medium. The electrode material includes an electrode active material as an essential component, and may also include binders, conductive materials, etc. as optional components. The liquid dispersion medium is a component that disperses the electrode material, and water, organic solvents, etc., are used. 【0015】Electrode active materials are materials that exhibit electrochemical capacity. For example, the electrode active material of a lithium-ion secondary battery exhibits capacity through oxidation-reduction reactions involving the insertion (intercalation) and deintercalation (release) of lithium ions. When the electrode to be manufactured is the negative electrode, carbon materials are used as the negative electrode active material. Examples of carbon materials include graphite, non-graphitizable carbon, and easily graphitizable carbon. When the electrode to be manufactured is the positive electrode, lithium-containing transition metal oxides, olivine-type lithium phosphate, etc., are used as the positive electrode active material. Examples of lithium-containing transition metal oxides include rock salt-type oxides with a layered structure such as lithium cobalt oxide, but are not particularly limited. 【0016】 Examples of binders include fluororesins such as polytetrafluoroethylene and polyvinylidene fluoride; acrylic resins such as methyl polyacrylate; rubbery materials such as styrene-butadiene rubber (SBR) and acrylic rubber; or mixtures thereof. Water-soluble resins such as carboxymethyl cellulose may also be used as thickeners. 【0017】 As the liquid dispersion medium, water, organic solvents, etc., can be used. Examples of organic solvents include alcohols such as ethanol, ethers such as tetrahydrofuran (THF), ketones such as acetone, and N-methyl-2-pyrrolidone (NMP). These may be used in mixtures. 【0018】 1.2 First Drying Step In the first drying step, the coating film is dried by irradiating the coated sheet with light in a drying line through which the coated sheet passes. This first drying step includes the remaining amount detection step and the first irradiation control step described below. The light to be irradiated is preferably light that can rapidly heat the irradiated object, or light that is easily absorbed by the slurry coating film. Examples of such light include, but are not limited to, laser light, halogen light, and infrared light. 【0019】The drying line is located downstream of the coating equipment in the transport path. The drying line is equipped with one or more light irradiation units that irradiate the coated sheets with light. The light irradiation units irradiate the coated sheets with light continuously or intermittently. Furthermore, the irradiated light may be subjected to pulse width modulation (PWM) or pulse frequency modulation (PFM). 【0020】 1.2.1 Remaining Amount Detection Process In the remaining amount detection process, the remaining amount of liquid dispersion medium in the coating film as it passes through the drying line is detected. However, it is not easy to directly measure the remaining amount of liquid dispersion medium in the coating film of a coated sheet while it is being transported. Therefore, the remaining amount of liquid dispersion medium may be detected or estimated indirectly. 【0021】 Here, while the surface temperature of the coating film gradually increases during light irradiation, it does not increase at a nearly constant rate with respect to the elapsed time. As shown in Figure 2 of Patent Document 1, the increase in the surface temperature of the coating film during light irradiation can be broadly divided into three sections. These are the preheating section in which the surface temperature rises rapidly, the constant-rate drying section in which the surface temperature becomes nearly constant, and the decrease-rate drying section in which the surface temperature rises rapidly again, leading to overheating. The reason why the surface temperature of the coating film remains nearly constant in the constant-rate drying section is that the amount of heating due to light irradiation is roughly balanced by the amount of heat removed by the heat of vaporization of the liquid dispersion medium. The ratio of the remaining amount of liquid dispersion medium during light irradiation decreases slowly in the preheating section, the decrease with respect to time becomes constant in the constant-rate drying section, and decreases slowly in the decrease-rate drying section. In other words, since the drying of the coating film is largely completed in the constant-rate drying section, the surface temperature of the coating film rises rapidly due to light irradiation from this section onward. 【0022】 1.2.2 First Irradiation Control Process In the first irradiation control process, the light irradiation termination point of the drying line is varied according to the detected remaining amount. The light irradiation termination point refers to, for example, which light irradiation unit to use to terminate light irradiation when multiple light irradiation units are arranged in the drying line. 【0023】With this configuration, by detecting the timing of the transition from the constant-rate drying section to the decreasing-rate drying section based on the ratio of the remaining amount of liquid dispersion medium during light irradiation and ending the light irradiation, it is possible to prevent the surface temperature of the coating film from rising rapidly and leading to overheating. As a result, it is possible to suppress the deterioration of the electrode sheet quality. 【0024】 In the first irradiation control step, the irradiation time, power, or both of the light at the light irradiation termination point may be varied. For example, if the light irradiation from each light irradiation unit is the same predetermined time or power, the irradiation time or power of the last light irradiation unit that terminates the light irradiation may be varied to be less than a predetermined energy density. This effectively prevents overheating of the coating film. The irradiation time or power of light irradiation units other than the last light irradiation unit may also be varied. Furthermore, a single light irradiation unit may have multiple light irradiation sections whose irradiation timing (on and off) is simultaneous. 【0025】 In the drying line, the coated sheet may be intermittently irradiated with light. In other words, intermittent irradiation may be performed, which involves alternating between periods of light irradiation and periods of light cessation. This not only slows down the rise in surface temperature of the coating compared to continuous light irradiation, but also allows for monitoring the rate of temperature change during the irradiation period and the rate of temperature change during the irradiation cessation period, thus more effectively preventing overheating of the coating. 【0026】 For example, the light irradiation termination point may be determined such that the remaining amount when discharged from the drying line is 40% or less of the dry moisture content (preferably within the range of 30% to 40%). 【0027】 1.3 Estimation of remaining amount based on temperature change rate The remaining amount detection step includes a temperature detection step for detecting the temperature of the coating film as it passes through the drying line, and a remaining amount calculation step for calculating the remaining amount based on the detected temperature change rate. 【0028】In the temperature detection process, the temperature of the coating film may be detected, for example, by a non-contact temperature sensor positioned to detect the temperature of the coating film passing through the drying line. Examples of such temperature sensors include, but are not limited to, radiation thermometers and thermal cameras that detect surface temperature by infrared radiation emitted from an object. In particular, with a thermal camera, the temperature distribution of the object surface is detected in two dimensions, making it possible to quickly detect a rapid rise in the temperature of the surrounding area where overheating is likely to occur. 【0029】 In the remaining amount calculation process, the remaining amount of the liquid dispersion medium is estimated and calculated based on the rate of change in temperature detected in the temperature detection process. The calculation formula for this purpose may, for example, be determined by establishing a basic mathematical formula and statistically determining its parameters from experimental data. However, the method of determination is not limited to this approach. 【0030】 The drying line has multiple light irradiation units that irradiate light onto coated sheets arranged along the conveying direction of the coated sheets, and the first irradiation control step may vary the light irradiation termination point by switching one or more downstream light irradiation units on and off. This makes it possible to effectively prevent overheating of the coating film with simple control. 【0031】 2. Method for Manufacturing an Electrode Sheet (2) The method for manufacturing an electrode sheet (2) comprises the transport step described above and the second drying step described below. In this manufacturing method as well, a coated sheet having a coating film of a slurry containing electrode material and liquid dispersion medium is transported on a drying line while the coating film is dried by light irradiation. However, it differs from the manufacturing method (1) described above in that the temperature of the coating film is detected during the transport of the coated sheet, and the light irradiation is directly controlled from the rate of change of the detected temperature. 【0032】 2.1 Second Drying Process In the second drying process, similar to the first drying process described above, the coating film is dried by irradiating the coated sheet with light in a drying line through which the coated sheet passes. This second drying process includes the temperature detection process described above and the second irradiation control process described below. The light used for irradiation is the same as that used in the first drying process described above. 【0033】2.2 Second Irradiation Control Step In the second irradiation control step, the light irradiation termination point of the drying line is varied according to the detected rate of change in temperature. In other words, in this second irradiation control step, the light irradiation termination point of the drying line is directly varied according to the detected rate of change in temperature, without calculating the remaining amount of liquid dispersion medium based on the detected rate of change in temperature. In the second irradiation control step, as in the first irradiation control step, the irradiation time or power of the light at the light irradiation termination point, or both, may be varied. In addition, the irradiation time or power or both of the light irradiation units other than the last light irradiation unit may be varied. 【0034】 With this configuration, by detecting the timing of the transition from the constant-rate drying section to the decreasing-rate drying section based on the rate of change in the temperature of the coating film during light irradiation and ending the light irradiation, it is possible to prevent the surface temperature of the coating film from rising rapidly and leading to overheating. As a result, it is possible to suppress the deterioration of the electrode sheet quality. 【0035】 The rate of temperature change at the end of light irradiation may be 1.4 times or more the rate of temperature change of the coating film immediately after it is brought into the drying line. 【0036】 In the second drying step, intermittent irradiation is performed, alternating between periods of light irradiation and periods of light cessation, and the rate of temperature change may be determined during either the irradiation period or the irradiation cessation period. This not only slows down the rise in the surface temperature of the coating film compared to continuous light irradiation, but also allows for referencing either or both of the rate of temperature change during the irradiation period and the rate of temperature change during the irradiation cessation period, as needed, thereby more effectively preventing overheating of the coating film. 【0037】3. Specific Examples of Electrode Sheet Manufacturing Methods Below, specific examples of electrode sheet manufacturing methods according to the present disclosure will be described in detail with reference to the drawings. The components and processes of the electrode sheet manufacturing methods described below can be applied to the components and processes described above and can be modified based on the above description. Furthermore, the matters described below may be applied to the above embodiments. Among the components and processes of the electrode sheet manufacturing methods described below, components and processes that are not essential to the electrode sheet manufacturing method according to the present disclosure may be omitted. Note that the figures shown below are schematic and do not accurately reflect the actual shape and number of components. 【0038】 Figure 1 is an explanatory diagram illustrating a manufacturing line 100 used in a method for manufacturing an electrode sheet according to one embodiment of the present disclosure. Figure 2 is a schematic graph showing the temporal change G2 of the surface temperature of the coating film during continuous irradiation with laser light. Figure 3 is a schematic graph showing the temporal change of the surface temperature of the coating film during intermittent irradiation with laser light. Figure 4 is a schematic graph showing the relationship between the number of intermittent laser irradiations and the heating / cooling rate. Figure 5 is a graph illustrating experimental data of the surface temperature and temperature change rate of the coating film during intermittent laser irradiation. Figure 6 is a graph illustrating the average temperature rise rate for 0.1 seconds after heating by each irradiation in Figure 5. Figure 7 is a graph illustrating experimental data of the temporal change of the surface temperature of the coating film according to the length of laser irradiation time. Figure 8 is a graph illustrating experimental data similar to that in Figure 7, but limited to after laser irradiation. Figure 9 is a distribution diagram showing experimental data of the relationship between dry-weight-based moisture content and heating rate. Figure 10 is a distribution diagram showing experimental data on the relationship between dry-weight moisture content and cooling rate. 【0039】3.1 Manufacturing Line 100 The manufacturing line 100 used in the electrode sheet manufacturing method of this embodiment comprises, as shown in Figure 1, an unwinding roll 10 for supplying the wound core material sheet S1, a coating device 20 for coating the core material sheet S1 with slurry, a transport path 30 for transporting the coated sheet S2 in a roll-to-roll manner, a drying line 40 for drying the coating film on the coated sheet S2, and a winding roll 50 for winding up the final electrode sheet S3. A rolling device, a firing device, and a slitting device are also arranged between the drying line 40 and the winding roll 50 of the manufacturing line 100, but their illustration and description are omitted. 【0040】 In the drying line 40, multiple laser irradiation units 41 are arranged at equal intervals along the transport path 30 to dry the coating film while transporting the coated sheet S2. Downstream of each laser irradiation unit 41, a thermal camera 42 is positioned to detect the surface temperature of the coating film on the coated sheet S2 as a two-dimensional image during laser irradiation (the thermal camera 42 for the rightmost laser irradiation unit 41 is not shown in the illustration). The number and arrangement of these units are not limited to the example shown. 【0041】 3.2 Changes in the surface temperature of the coating film on the coated sheet S2 When the coated sheet S2 is continuously irradiated with laser light, as shown in G2 of Figure 2, the temperature of the coating film rises sharply in the preheating section described above, and the surface temperature is maintained almost constant in the subsequent constant-rate drying section. Immediately after that, the surface temperature begins to rise sharply again, and it is thought that overheating has already occurred at the edges of the coating film at this point (G23). In order to prevent overheating, it is necessary to detect the temperature at a point (G21) even earlier than the end of the constant-rate drying section (G22). 【0042】Therefore, when the laser light is intermittently irradiated to gently increase the surface temperature of the coating film of the coating sheet S2, as shown in G3 of FIG. 3, the maximum value of the surface temperature at each irradiation is maintained almost constant up to about several times. After that, since the surface temperature starts to rise rapidly, it is considered that overheating has already occurred at the end of the coating film or the like at this point (G33). Assuming that the irradiation immediately before that is the end point (G32) of the constant rate drying section, if the irradiation point (G31) immediately before that can be detected, it becomes possible to prevent overheating of the coating film. 【0043】 As shown in G4 of FIG. 4, the relationship between the number of intermittent irradiations of the laser light and the heating / cooling rate (temperature change rate) is such that the heating rate increases at a constant rate up to a certain number of times (in this example, a total of 5 times from G41 to G45). After that (in this example, G46 and G47), the increase in the heating rate becomes rapid. By detecting the timing at which the heating rate rapidly increases in this way, it is possible to prevent the surface temperature of the coating film from rising rapidly and reaching overheating. As a result, it becomes possible to suppress deterioration of the quality of the electrode sheet. 【0044】 3.3 Experimental data on changes in the surface temperature of the coating film of the coating sheet S2 The experimental data on the surface temperature and the temperature change rate of the coating film during the intermittent irradiation of the laser light shown in FIG. 3 are as shown in FIG. 5, for example. Also, the average temperature increase rate for 0.1 seconds after heating by each irradiation is as shown in FIG. 6, for example. Thus, it can be seen that the heating rate increases as the number of laser light irradiations increases. This suggests that the heat capacity is decreasing due to the decrease in the remaining amount of the liquid dispersion medium. Therefore, it becomes possible to estimate the remaining amount of the liquid dispersion medium based on the heating / cooling rate, that is, the temperature change rate. 【0045】 However, since there are many uncertain factors in the first laser light irradiation and the possibility of reaching immediately before overheating in the first irradiation is small, it is preferable to exclude it from the detection target of the temperature change rate for laser light irradiation control. This makes it possible to prevent deterioration of the quality of the electrode sheet due to incorrect laser light irradiation control. 【0046】Further, the temporal change in the surface temperature of the coating film according to the length of the irradiation time of the laser light is as shown in, for example, FIG. 7. If this temporal change is limited after the laser light irradiation, it becomes as shown in FIG. 8. As can be seen by comparing these, the rate of temperature increase during the irradiation period of the laser light shows almost no difference depending on the length of the irradiation time of the laser light. On the other hand, a clear difference depending on the length of the irradiation time of the laser light is seen in the rate of temperature decrease during the period when the laser light irradiation is stopped. Therefore, accurate control of the laser light irradiation can be achieved based on the rate of temperature decrease during the period when the laser light irradiation is stopped. 【0047】 The relationship between the moisture content on a dry basis and the rate of temperature increase is as shown in, for example, the distribution diagram shown in FIG. 9. On the other hand, the relationship between the moisture content on a dry basis and the rate of temperature decrease is as shown in, for example, the distribution diagram shown in FIG. 10. As can be seen from these distribution diagrams, as a threshold value for determining the end point of the laser light irradiation, for example, the remaining amount of the residual liquid dispersion medium when carried out from the drying line may be 40% or less of the moisture content on a dry basis. Also, the time when the rate of temperature change of the coating film becomes 1.4 times or more that of the rate of temperature change immediately after loading onto the drying line may be set as the end point of the laser light irradiation. 【0048】 The present disclosure is not limited to the above-described embodiments, and can be implemented in various aspects without departing from the gist thereof. Also, various disclosed configurations can be formed by appropriately combining a plurality of components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiments. The drawings are schematically shown mainly for each component for easy understanding, and the number of each component shown in the drawings may be different from the actual situation for convenience of drawing creation. Also, each component shown in the above embodiments is an example and is not particularly limited, and various changes can be made without substantially departing from the effects of the present disclosure. 【0049】4. The following technologies are disclosed by the above descriptions of embodiments. (Technology 1) A method for manufacturing an electrode sheet, comprising: a transport step of transporting a coated sheet having a coating film of a slurry containing an electrode material and a liquid dispersion medium; and a first drying step of drying the coating film by irradiating the coated sheet with light in a drying line through which the coated sheet passes, wherein the first drying step includes: a remaining amount detection step of detecting the remaining amount of the liquid dispersion medium in the coating film as it passes through the drying line; and a first irradiation control step of varying the light irradiation end point of the drying line according to the detected remaining amount. (Technology 2) The method for manufacturing an electrode sheet according to Technology 1, wherein the first irradiation control step varies the irradiation time or power of the light at the light irradiation end point. (Technology 3) The method for manufacturing an electrode sheet according to Technology 1 or 2, wherein the coating sheet is intermittently irradiated with light in the drying line. (Technology 4) A method for manufacturing an electrode sheet according to any one of Techniques 1 to 3, wherein the light irradiation termination point is determined such that the remaining amount when discharged from the drying line is 40% or less of the dry moisture content. (Technology 5) A method for manufacturing an electrode sheet according to any one of Techniques 1 to 4, wherein the remaining amount detection step includes a temperature detection step for detecting the temperature of the coating film when it is passing through the drying line, and a remaining amount calculation step for calculating the remaining amount based on the detected rate of change of the temperature. (Technology 6) A method for manufacturing an electrode sheet according to any one of Techniques 1 to 5, wherein the drying line has a plurality of light irradiation units that irradiate the coated sheets with light arranged along the transport direction of the coated sheets, and the first irradiation control step varies the light irradiation termination point by switching one or more of the downstream light irradiation units on and off.(Technical 7) A method for manufacturing an electrode sheet, comprising: a conveying step of conveying a coated sheet having a coating film of a slurry containing an electrode material and a liquid dispersion medium; and a second drying step of drying the coating film by irradiating the coated sheet with light in a drying line through which the coated sheet passes, wherein the second drying step includes a temperature detection step of detecting the temperature of the coating film as it passes through the drying line; and a second irradiation control step of varying the light irradiation end point of the drying line according to the detected rate of change of the temperature. (Technical 8) The method for manufacturing an electrode sheet according to Technical 7, wherein the rate of change of the temperature at the light irradiation end point is 1.4 times or more the rate of change of the temperature of the coating film immediately after it is brought into the drying line. (Technical 9) The method for manufacturing an electrode sheet according to Technical 7 or 8, wherein in the second drying step, intermittent irradiation is performed by repeating an irradiation period in which the light is irradiated and an irradiation stop period in which the light irradiation is stopped, and the rate of change of the temperature is determined during the irradiation period or the irradiation stop period. (Technical 10) A method for manufacturing an electrode sheet according to any one of Technical 1 to 9, wherein the light is laser light. 【0050】 This disclosure can be used in a method for manufacturing electrode sheets. 【0051】 Although the present invention has been described in relation to preferred embodiments at present, such disclosure should not be interpreted restrictively. Various modifications and alterations will undoubtedly become apparent to those skilled in the art in the field to which the invention pertains by reading the above disclosure. Accordingly, the appended claims should be interpreted as encompassing all modifications and alterations without departing from the true spirit and scope of the invention. 【0052】 10 Unwinding roll 20 Coating equipment 30 Conveyor path 40 Drying line 41 Laser irradiation unit 42 Thermal camera 50 Unwinding roll 100 Manufacturing line
Claims
1. A method for manufacturing an electrode sheet, comprising: a conveying step of conveying a coated sheet having a coating film of a slurry containing an electrode material and a liquid dispersion medium; and a first drying step of drying the coating film by irradiating the coated sheet with light in a drying line through which the coated sheet passes, wherein the first drying step includes a remaining amount detection step of detecting the remaining amount of the liquid dispersion medium in the coating film as it passes through the drying line, and a first irradiation control step of varying the light irradiation end point of the drying line according to the detected remaining amount.
2. The method for manufacturing an electrode sheet according to claim 1, wherein the first irradiation control step varies the irradiation time or power of the light at the light irradiation termination point.
3. The method for manufacturing an electrode sheet according to claim 1 or 2, wherein the drying line intermittently irradiates the coated sheet with the light.
4. The method for manufacturing an electrode sheet according to claim 1 or 2, wherein the light irradiation termination point is determined such that the remaining amount when discharged from the drying line is 40% or less of the dry moisture content.
5. The method for manufacturing an electrode sheet according to claim 1 or 2, wherein the remaining amount detection step includes a temperature detection step for detecting the temperature of the coating film as it passes through the drying line, and a remaining amount calculation step for calculating the remaining amount based on the detected rate of change of the temperature.
6. The method for manufacturing an electrode sheet according to claim 1 or 2, wherein the drying line has a plurality of light irradiation units that irradiate the coated sheets with light arranged along the transport direction of the coated sheets, and the first irradiation control step varies the light irradiation termination point by switching one or more of the downstream light irradiation units on and off.
7. A method for manufacturing an electrode sheet, comprising: a conveying step of conveying a coated sheet having a coating film of a slurry containing an electrode material and a liquid dispersion medium; and a second drying step of drying the coating film by irradiating the coated sheet with light in a drying line through which the coated sheet passes, wherein the second drying step includes a temperature detection step of detecting the temperature of the coating film as it passes through the drying line; and a second irradiation control step of varying the light irradiation end point of the drying line according to the rate of change of the detected temperature.
8. The method for manufacturing an electrode sheet according to claim 7, wherein the rate of change of temperature at the end point of light irradiation is 1.4 times or more the rate of change of temperature of the coating film immediately after it is introduced into the drying line.
9. The method for manufacturing an electrode sheet according to claim 7 or 8, wherein the second drying step involves performing intermittent irradiation by repeatedly alternating between an irradiation period in which the light is irradiated and an irradiation stop period in which the irradiation of the light is stopped, and the rate of change of the temperature is determined during the irradiation period or the irradiation stop period.
10. The method for manufacturing an electrode sheet according to claim 1 or 7, wherein the light is laser light.