Roller press rolling force control method and device and roller press

Abstract

This application relates to a method, apparatus, and rolling mill for controlling the rolling force of a rolling mill. The method includes: determining a feedforward rolling force for rolling the electrode sheet using a rolling mill based on at least two preset parameters of the electrode sheet; determining a corrected rolling force for rolling the electrode sheet by querying a preset database based on acquired sensor signal values; inputting a first deviation value between the feedforward rolling force and the corrected rolling force into a PID controller to obtain a rolling force correction amount output by the PID controller; determining a target rolling force for rolling the electrode sheet based on the feedforward rolling force and the rolling force correction amount, and outputting a rolling force control command based on the target rolling force. The solution provided by this application can improve the response speed and steady-state accuracy of the rolling force control of the rolling mill, output a balanced and accurate rolling force, and ensure the consistency of the electrode sheet thickness.

Description

Technical Field

[0001] This application relates to the field of battery electrode production technology, and in particular to a method, device and roller press for controlling rolling force of a roller press. Background Technology

[0002] The related technology for controlling the rolling force of lithium battery electrode roll mills employs a linear control assumption. This is based on the approximate linear relationship between the applied rolling force F and the roll gap S, the electrode inlet thickness H_in, and the outlet thickness H_out. Furthermore, within the range of the rolling force sensor, the output signal of the rolling force sensor exhibits a strictly linear relationship with the applied rolling force F (the actual rolling force experienced by the electrode) (with a constant proportionality coefficient). Linear PID control is then implemented based on the linear deviation between the measured rolling force and the target rolling force. Within a stable electrode material range and a relatively small variation in rolling force, the linear approximation is acceptable.

[0003] However, in the control methods of related technologies, there is a significant nonlinear relationship between the output signal of the rolling force sensor and the applied rolling force F. The sensitivity of resistance strain gauge rolling force sensors varies considerably in the low-range (<20%FS (Full Scale, representing the maximum range of the measuring device or sensor)) and high-range (>80%FS) sections. The linear assumption leads to measurement deviations (the deviation between the measured rolling force value after linear conversion of the resistance strain gauge rolling force sensor output signal (voltage / current) and the actual rolling force) reaching ±1.5%FS or higher. Furthermore, due to the elastoplastic constitutive relationship of the electrode material and the elastic flattening of the rolls, the applied rolling force F and the electrode thickness reduction exhibit a power function or exponential relationship. The relationship between the applied rolling force F and the electrode thickness is inherently nonlinear. The linear PID control of related technologies responds slowly when the deviation is small and is prone to overshoot when the deviation is large.

[0004] Therefore, under the mutual coupling of multiple sources of errors in the lithium battery electrode rolling process, such as sensor error, mechanical wear and gap, fluctuation of electrode material characteristics, rolling speed variation, uneven edge pressure distribution, and imbalance of left and right rolling forces, the related lithium battery electrode rolling mill rolling force control method relies on the integral action of PID to slowly eliminate the errors and perform linear PID control. This results in inaccurate output rolling force, causing rolling force control response lag, unbalanced rolling force output, difficulty in controlling electrode edge quality, and poor electrode thickness consistency. Summary of the Invention

[0005] To address or partially address the problems existing in related technologies, this application provides a rolling force control method, device, and rolling mill for a rolling mill, which can improve the steady-state accuracy of rolling force control, output a balanced and accurate rolling force, and improve the response speed of rolling force control and the consistency of electrode thickness.

[0006] The first aspect of this application provides a method for controlling the rolling force of a roller press, the method comprising: The feedforward rolling force for rolling the electrode is determined by the roller press based on at least two preset parameters of the electrode. The corrective rolling force for rolling the electrode sheet is determined by querying a preset database based on the acquired sensor signal values. The first deviation value between the feedforward rolling force and the corrected rolling force is input into the PID controller to obtain the rolling force correction amount output by the PID controller; Based on the feedforward rolling force and the rolling force correction, a target rolling force is determined for rolling the electrode sheet, and a rolling force control command is output based on the target rolling force.

[0007] In one embodiment, the step of querying a preset database based on the acquired sensor signal values ​​to determine the corrective rolling force for rolling the electrode sheet includes: Based on the real-time output value of the pressure sensor, the output value range in which the real-time output value is located, the standard rolling force corresponding to the start point of the output value range, and the standard rolling force corresponding to the end point of the output value range are obtained by querying the preset database. The corrected rolling force for rolling the electrode sheet is calculated based on the real-time output value, the output value corresponding to the start point of the output value interval and the standard rolling force, and the output value corresponding to the end point of the output value interval and the standard rolling force.

[0008] In one implementation, the preset database includes a piecewise linear interpolation lookup table, which is pre-established in the following manner: The full scale of the pressure sensor is evenly segmented to obtain I calibration pressure points within the full scale, where I is a positive integer greater than 2. Based on the original output value of the pressure sensor at each of the I calibrated pressure points and the I standard rolling forces corresponding to each of the I calibrated pressure points, a linear correspondence between the original output value of the pressure sensor and the standard rolling forces is determined, and the piecewise linear interpolation lookup table is established.

[0009] In one embodiment, calculating the corrected rolling force for rolling the electrode sheet based on the real-time output value, the output value corresponding to the start point of the output value interval and the standard rolling force, and the output value corresponding to the end point of the output value interval and the standard rolling force includes: When the real-time output value U_raw∈[U_raw_i, U_raw_{i+1}], the standard rolling force F_std_i corresponding to the starting point U_raw_i of the output value interval and the standard rolling force F_std_{i+1} corresponding to the ending point U_raw_{i+1} of the output value interval are obtained, and the corrected rolling force for rolling the electrode sheet is calculated using the following formula. ,in, , U_raw_i is the original output value of the pressure sensor at the i-th calibration pressure point among the I calibration pressure points, and U_raw_{i+1} is the original output value of the pressure sensor at the (i+1)-th calibration pressure point among the I calibration pressure points.

[0010] In one embodiment, the step of inputting a first deviation value between the feedforward rolling force and the corrected rolling force into a PID controller to obtain the rolling force correction amount output by the PID controller includes: Obtain the outer ring correction amount of the rolled electrode sheet; The feedforward rolling force is corrected using the outer ring correction amount to obtain the corrected feedforward rolling force; The first deviation value between the corrected feedforward rolling force and the corrected rolling force is input into the PID controller to obtain the rolling force correction amount output by the PID controller.

[0011] In one embodiment, determining the feedforward rolling force for rolling the electrode using a roller press based on at least two preset parameters of the electrode includes: The feedforward rolling force for rolling the electrode sheet is calculated based on the width, deformation resistance, original thickness before rolling, and target thickness after rolling.

[0012] In one embodiment, the method further includes: Based on the second deviation between the measured rolling force at the target time and the feedforward rolling force, the deformation resistance is updated using a single-parameter recursive least squares method; or, Based on the second deviation between the measured rolling force at the target time and the feedforward rolling force, a PI controller is used to update the deformation resistance.

[0013] A second aspect of this application provides a rolling force control device for a roller press, the device comprising: The feedforward module is used to determine the feedforward rolling force of the roller press for rolling the electrode sheet based on at least two preset parameters of the electrode sheet; The calibration module is used to query a preset database based on the acquired sensor signal values ​​to determine the calibration rolling force for rolling the electrode sheet; The calculation module is used to input the first deviation value between the feedforward rolling force determined by the feedforward module and the correction rolling force determined by the correction module into the PID controller to obtain the rolling force correction amount output by the PID controller; The correction module is used to determine the target rolling force for rolling the electrode sheet based on the feedforward rolling force determined by the feedforward module and the rolling force correction amount calculated by the calculation module, so as to output a rolling force control command based on the target rolling force.

[0014] In one embodiment, the device further includes: The update module is used to update the deformation resistance of the electrode sheet using a single-parameter recursive least squares method based on the second deviation value between the measured rolling force at the target time and the feedforward rolling force determined by the feedforward module; or, The update module is used to update the deformation resistance of the electrode sheet using a PI controller based on the second deviation value between the measured rolling force at the target time and the feedforward rolling force determined by the feedforward module.

[0015] A third aspect of this application provides a roller press, the roller press including the roller press rolling force control device as described above.

[0016] A fourth aspect of this application provides an electronic device, comprising: Processor; and A memory that stores executable code, which, when executed by the processor, causes the processor to perform the method described above.

[0017] A fifth aspect of this application provides a computer-readable storage medium having executable code stored thereon, which, when executed by a processor, causes the processor to perform the method described above.

[0018] A sixth aspect of this application provides a computer program product comprising computer instructions that, when executed by a processor, implement the method described above.

[0019] The technical solution provided in this application may include the following beneficial results: The technical solution of this application calculates the corrected rolling force of the rolled electrode sheet by looking up a table using piecewise linear interpolation based on the real-time output value of the pressure sensor; calculates the rolling force correction amount based on the first deviation between the feedforward rolling force and the corrected rolling force of the rolled electrode sheet; and calculates the target rolling force of the rolled electrode sheet based on the feedforward rolling force and the rolling force correction amount. By combining the feedforward rolling force calculation with the rolling force correction, the steady-state accuracy of the rolling force control of the rolling mill can be improved, resulting in a balanced and accurate rolling force output. This also improves the dynamic response speed of the rolling force control, reducing the response time of the rolling force control from 0.8s to 0.4s, the overshoot from 18% to 4%, and the steady-state error from ±2.3%FS to ±0.8%FS. The step response time of the rolling force control is reduced by 50%, and the overshoot is reduced from 15% to 3%. The rolling force control method of the roller press in this application can improve the steady-state accuracy of the rolling force control of the roller press, output a balanced and accurate rolling force, improve the dynamic response speed of the rolling force control, improve the efficiency of the electrode rolling, and ensure the consistency of the electrode thickness.

[0020] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0021] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0022] Figure 1 This is a schematic flowchart illustrating the rolling force control method for a roller press according to an embodiment of this application; Figure 2 This is another schematic flowchart illustrating the rolling force control method of a roller press as shown in the embodiments of this application; Figure 3 This is another schematic flowchart illustrating the rolling force control method of a roller press as shown in the embodiments of this application; Figure 4 This is a schematic flowchart illustrating the method for controlling the rolling force of a roll press in each control cycle, as shown in an embodiment of this application. Figure 5 This is a schematic diagram of the structure of the rolling force control device for a roller press shown in the embodiments of this application; Figure 6 This is a schematic diagram of the rolling force control system of the roller press shown in the embodiments of this application; Figure 7 This is a partial structural schematic diagram of the rolling force control system of the roller press shown in the embodiments of this application; Figure 8 This is a schematic diagram of the structure of an electronic device shown in an embodiment of this application. Detailed Implementation

[0023] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0024] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0025] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0026] This application provides a method for controlling the rolling force of a roller press, which can improve the response speed and steady-state accuracy of the rolling force control of the roller press, output a balanced and accurate rolling force, and ensure the consistency of the electrode thickness.

[0027] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic flowchart illustrating a method for controlling the rolling force of a roller press, as shown in an embodiment of this application.

[0029] See Figure 1 A method for controlling the rolling force of a roller press, comprising: Step 101: Determine the feedforward rolling force of the roller press for rolling the electrode sheet based on at least two preset parameters of the electrode sheet.

[0030] In one embodiment, the feedforward rolling force of the rolled electrode can be calculated based on the electrode width, deformation resistance, original thickness before rolling, target thickness after rolling, and roll radius. Combining the design parameters, process parameters, and testing equipment of the lithium-ion battery electrode, the electrode width, deformation resistance, original thickness before rolling, and target thickness after rolling are obtained. The roll radius of the rolled electrode is obtained from the equipment nameplate or technical manual of the rolling mill, or through on-site measurement. The feedforward rolling force of the rolled electrode is calculated based on the electrode width, deformation resistance, original thickness before rolling, target thickness after rolling, and roll radius.

[0031] Step 102: Query the preset database based on the acquired sensor signal values ​​to determine the corrective rolling force of the rolled electrode sheet.

[0032] In one embodiment, when rolling the electrode sheet in a roller press, the rolling force of the roller press can be measured in real time by a pressure sensor, and the real-time output value of the pressure sensor can be obtained in real time. By querying a piecewise linear interpolation lookup table, the output value range in which the real-time output value is located can be obtained (for example, the output value range is between 20%FS and 30%FS). Based on the output value range in which the real-time output value is located, the output values ​​corresponding to the start and end points of the output value range, as well as the standard rolling forces corresponding to the start and end points of the output value range, are obtained respectively. Based on the real-time output value of the pressure sensor, the output values ​​corresponding to the start and end points of the output value range, and the standard rolling forces corresponding to the start and end points of the output value range, the corrected rolling force of the rolled electrode sheet is calculated in real time.

[0033] Step 103: Input the first deviation value between the feedforward rolling force and the corrected rolling force of the rolled electrode into the PID controller to obtain the rolling force correction amount output by the PID controller.

[0034] In one embodiment, a first deviation value between the feedforward rolling force and the corrected rolling force of the rolled electrode can be calculated based on the feedforward rolling force and the corrected rolling force of the rolled electrode; the first deviation value is input into the PID controller to obtain the rolling force correction amount output by the PID controller.

[0035] Step 104: Determine the target rolling force of the rolled electrode based on the feedforward rolling force and the rolling force correction amount, and output the rolling force control command according to the target rolling force.

[0036] In one embodiment, the target rolling force of the rolled electrode can be calculated in real time based on the feedforward rolling force and the rolling force correction amount calculated in real time, and the target rolling force of the rolled electrode can be input into the rolling mill servo valve; the rolling mill servo valve outputs the target rolling force control command in real time according to the target rolling force.

[0037] The rolling force control method for a roller press in this embodiment calculates the corrected rolling force of the roller pressing electrode by looking up a table using piecewise linear interpolation based on the real-time output value of the pressure sensor; it calculates the rolling force correction amount based on the first deviation between the feedforward rolling force and the corrected rolling force of the roller pressing electrode; and it calculates the target rolling force of the roller pressing electrode based on the feedforward rolling force and the rolling force correction amount. By combining the feedforward rolling force calculation with the rolling force correction, the steady-state accuracy of the roller press rolling force control can be improved, resulting in a balanced and accurate rolling force output. This also improves the dynamic response speed of the rolling force control, reducing the response time from 0.8s to 0.4s, the overshoot from 18% to 4%, and the steady-state error from ±2.3%FS to ±0.8%FS. The step response time of the rolling force control is reduced by 50%, and the overshoot is reduced from 15% to 3%. The rolling force control method of the roller press in this application can improve the steady-state accuracy of the rolling force control of the roller press, output a balanced and accurate rolling force, improve the dynamic response speed of the rolling force control, improve the efficiency of the electrode rolling, and ensure the consistency of the electrode thickness.

[0038] Figure 2 This is another schematic flowchart illustrating a method for controlling the rolling force of a roller press, as shown in an embodiment of this application. Figure 3 This is another schematic flowchart illustrating the rolling force control method of a roller press as shown in the embodiments of this application; Figure 4 This is a schematic flowchart illustrating the method for controlling the rolling force of a roll press in each control cycle, as shown in an embodiment of this application. Figures 2-4 The technical solution of this application is described in more detail.

[0039] In one embodiment, a control period (e.g., 10ms) can be set. The rolling force control method of the roller press embodiment of this application is executed cyclically according to the set control period to realize dynamic control of the rolling force of the roller press, so as to improve the accuracy of the rolling force of the roller press and ensure the consistency of the electrode thickness.

[0040] See Figures 2-4 A method for controlling the rolling force of a roller press, comprising: Step 201: Obtain the width, deformation resistance, original thickness before rolling, and target thickness after rolling of the electrode sheet.

[0041] In one embodiment, the width w, deformation resistance K, original thickness h_in before rolling, and target thickness h_target after rolling of the electrode can be obtained by combining the design parameters, process parameters, and testing equipment of the lithium-ion battery electrode.

[0042] Step 202: Calculate the feedforward rolling force of the rolled electrode based on the electrode width, deformation resistance, original thickness before rolling, target thickness after rolling, and roll radius.

[0043] In one embodiment, the electrode rolling process can be approximated as a plane strain compression process, and the rolling force F and the electrode thickness reduction Δh satisfy a power function relationship, i.e.: ; Where K represents the deformation resistance of the electrode sheet, in MPa (megapascals); w represents the width of the electrode sheet, in mm (millimeters); R represents the roll radius, in mm; and Δh represents the electrode sheet thickness reduction Δh, in mm.

[0044] In one embodiment, the feedforward rolling force F_ff of the rolled electrode can be calculated using a nonlinear feedforward model based on the electrode's deformation resistance K, width w, original thickness h_in, actual target thickness h_target, and roll radius R. .

[0045] In one embodiment, the thickness reduction Δh_target of the electrode can be calculated based on the original thickness h_in before electrode rolling and the target thickness h_target (electrode exit thickness) after electrode rolling. Δh_target = h_in - h_target.

[0046] In one embodiment, the target thickness h_target after the electrode is rolled can be measured in real time using a thickness gauge.

[0047] In one embodiment, during the stable rolling stage of the roll forming process, the measured rolling force of the roll forming electrode at the target time can be obtained by a pressure sensor; the deformation resistance can be updated based on the second deviation value between the measured rolling force at the target time and the feedforward rolling force of the roll forming electrode; and the feedforward rolling force of the roll forming electrode at the target time can be calculated based on the electrode width, the original thickness before roll forming, the target thickness after roll forming, the updated deformation resistance, and the roll radius.

[0048] In one embodiment, the deformation resistance can be updated using a single-parameter recursive least squares (RLS) method based on the second deviation between the measured rolling force at the target time and the feedforward rolling force of the rolled electrode. Based on the difference ΔF_ff_target between the measured rolling force F_meas_target at the target time and the feedforward rolling force F_ff_target calculated by the nonlinear feedforward model, the deformation resistance K_old of the electrode at the target time is corrected online at a set update cycle (e.g., every 1 second) to obtain the corrected deformation resistance K_new. The deformation resistance K of the electrode is then updated to the corrected deformation resistance K_new. ; Where η represents the learning rate, and its value ranges from 0.1 to 0.5. ; w represents the width of the electrode sheet in mm (millimeters); R represents the radius of the roll in mm; h_target = h_in - h_target.

[0049] In one embodiment, the deformation resistance can be updated using a PI (Proportional-Integral Controller) based on the second deviation between the measured rolling force and the feedforward rolling force at the target time. Based on the difference ΔF_ff_target between the measured rolling force F_meas_target and the feedforward rolling force F_ff_target calculated by the nonlinear feedforward model at the target time, the PI controller corrects the deformation resistance K_old of the electrode at the target time online at a set update cycle (e.g., every 1 second), obtaining the corrected deformation resistance K_new. The deformation resistance K of the electrode is then updated to the corrected deformation resistance K_new. ; Among them, e=F_meas_target-F_ff_target=ΔF_ff_target; K p For proportional gain; K i This is the integral gain; This is the integral term of the difference ΔF_ff_target.

[0050] Step 203: Based on the real-time output value of the pressure sensor, calculate the corrective rolling force of the rolled electrode by querying a preset database.

[0051] In one embodiment, the preset database may include a piecewise linear interpolation lookup table, which can uniformly divide the full scale (0%FS-100%FS) of the pressure sensor into I calibrated pressure points at the full scale, where I is a positive integer greater than 2; based on the original output value of the pressure sensor at each of the I calibrated pressure points and the I standard rolling forces corresponding to each of the I calibrated pressure points, the linear correspondence between the original output value of the pressure sensor and the standard rolling forces is determined, and a piecewise linear interpolation lookup table is established.

[0052] In one embodiment, static offline calibration can be used to correct the nonlinearity between the pressure sensor output value and the rolling force, establishing a piecewise linear interpolation lookup table that corresponds one-to-one with the standard rolling force. During the installation and commissioning phase of the roll press, static offline calibration is performed on each pressure sensor. I calibration pressure points are selected within the full-scale range of the pressure sensor (0%FS~100%FS) (e.g., 11 calibration pressure points: 0%FS, 10%FS, 20%FS, 30%FS, 40%0%FS, 50%0%FS, 60%0%FS, 70%0%FS, 80%0%FS, 90%0%FS, 100%FS). A standard load is applied at each of the I calibration pressure points using a high-precision press, and the standard rolling force F_std_i (i= 1, 2, 3, ..., I), and record the original output value U_raw_i (voltage or current) of each pressure sensor at each of the I calibration pressure points i; map the original output value U_raw_i to the standard rolling force F_std_i one-to-one, with U_raw_i as the independent variable and F_std_i as the dependent variable, and determine the linear correspondence between the original output value of the pressure sensor and the standard rolling force through a piecewise linear interpolation function, and establish a piecewise linear interpolation lookup table that maps the original output value of the pressure sensor to the standard rolling force one-to-one.

[0053] In one embodiment, during the rolling process of the rolled electrode sheet, the real-time output value U_raw_target of the pressure sensor at the target time can be acquired in real time; based on the real-time output value U_raw_target of the pressure sensor, by querying a piecewise linear interpolation lookup table, the output value interval [U_raw_i, U_raw_{i+1}] in which the real-time output value U_raw_target is located, the standard rolling force F_std_i corresponding to the starting point U_raw_i of the output value interval [U_raw_i, U_raw_{i+1}], and the standard rolling force F_std_{i+1} corresponding to the ending point U_raw_{i+1} of the output value interval [U_raw_i, U_raw_{i+1}] can be obtained; based on the real-time output value Given U_raw_target, the starting point U_raw_i of the output value interval [U_raw_i, U_raw_{i+1}], the ending point U_raw_{i+1} of the output value interval [U_raw_i, U_raw_{i+1}], the output value U_raw_i corresponding to the starting point U_raw_i of the output value interval [U_raw_i, U_raw_{i+1}], and the standard rolling force F_std_i, and the output value U_raw_{i+1} corresponding to the ending point U_raw_{i+1} of the output value interval [U_raw_i, U_raw_{i+1}], and the standard rolling force F_std_{i+1}, calculate the corrected rolling force F_corrected_target for the rolled electrode sheet, i.e.: When the real-time output value of the pressure sensor is U_raw_target∈[U_raw_i, U_raw_{i+1}], the standard rolling force F_std_i corresponding to U_raw_i and the standard rolling force F_std_{i+1} corresponding to U_raw_{i+1} are obtained, and the corrected rolling force of the rolled electrode is calculated using the following formula. _target, where, .

[0054] Step 204: Calculate the first deviation value based on the feedforward rolling force and the corrective rolling force of the rolled electrode.

[0055] In one embodiment, the deviation between the feedforward rolling force F_ff_target and the corrected rolling force F_corrected_target can be calculated based on the feedforward rolling force F_ff_target and the corrected rolling force F_corrected_target at the target time, and the first deviation value at the target time can be calculated. F, where F=F_ff_target-F_corrected_target.

[0056] In one embodiment, the outer ring correction amount of the rolled electrode can be obtained; the feedforward rolling force of the rolled electrode at the target time is corrected using the outer ring correction amount to obtain the corrected feedforward rolling force; and a first deviation value is calculated based on the corrected feedforward rolling force and the corrected rolling force. F.

[0057] In one embodiment, an outer ring correction factor F_oc can be used to correct the feedforward rolling force F_ff_target of the rolled electrode at the target time, thereby obtaining the corrected feedforward rolling force (F_ff_target + F_oc) at the target time. Based on the corrected feedforward rolling force (F_ff_target + F_oc) and the corrected rolling force F_corrected_target at the target time, the first deviation value of the corrected feedforward rolling force (F_ff_target + F_oc) and the corrected rolling force F_corrected_target at the target time is calculated. F, where F=(F_ff_target+F_oc)-F_corrected_target.

[0058] In one embodiment, the outer loop correction F_oc may include all additional corrections independent of the main controller (e.g., nonlinear feedforward model and PID controller), specifically including process corrections and / or thickness corrections.

[0059] In one embodiment, the process correction amount is a type of outer loop correction amount, which refers to the correction amount calculated by looking up a table or mathematical model based on changes in rolling process parameters (e.g., roll temperature, lubrication status).

[0060] In one embodiment, the thickness correction amount can be based on the thickness deviation eh of the rolled electrode sheet (eh = h_target). h_actual (h_actual is the actual thickness of the electrode after rolling, measured by a thickness gauge), is a correction amount calculated using a PI controller.

[0061] Step 205: Input the first deviation value between the corrected feedforward rolling force and the corrected rolling force into the PID controller to obtain the rolling force correction amount output by the PID controller.

[0062] In one embodiment, the first deviation value at the target time can be used as a basis. F, the first deviation value F is input to the PID controller, which then uses the first deviation value... F calculates the rolling force correction u_PID at the target time, where, ; Kp represents the proportional parameter of the PID controller; Ki represents the integral parameter of the PID controller; Kd represents the derivative parameter of the PID controller. Indicates rolling force deviation The integral term of F; Indicates rolling force deviation The differential term of F.

[0063] Step 206: Calculate the target rolling force at the target time based on the corrected feedforward rolling force and the rolling force correction amount at the target time, so that the roll press outputs the rolling force control command at the target time according to the target rolling force.

[0064] In one embodiment, the target rolling force F_cmd at the target time can be calculated based on the corrected feedforward rolling force (F_ff_target+F_oc) and the rolling force correction amount u_PID at the target time, and the target rolling force F_cmd at the target time can be input into the roller press servo valve; the roller press servo valve outputs the rolling force control command at the target time based on the target rolling force F_cmd at the target time.

[0065] In one embodiment, the corrected feedforward rolling force (F_ff_target + F_oc) at the target time can be added to the rolling force correction amount u_PID to calculate the target rolling force F_cmd at the target time. F_cmd=(F_ff_target+F_oc)+u_PID.

[0066] The rolling force control method for the roller press in this application calculates the corrected rolling force of the roller pressing electrode based on the real-time output value of the pressure sensor by consulting a lookup table using piecewise linear interpolation. It uses piecewise linear interpolation to correct the nonlinearity between the pressure sensor output and the standard rolling force, reducing the pressure sensor measurement error from ±1.5%FS to within ±0.2%FS. This explicitly compensates for the nonlinearity of the pressure sensor and the rolling process, achieving a full-range rolling force control accuracy of ±1.0%FS, which is superior to the ±2%~±3%FS of related technologies. Furthermore, by consulting a lookup table using piecewise linear interpolation to calculate the corrected rolling force of the roller pressing electrode, the response time of the rolling force control is shortened from 0.8s to 0.4s, the overshoot is reduced from 18% to 4%, and the steady-state error is reduced from ±2.3%FS to ±0.8%FS. Based on the first deviation between the feedforward rolling force and the corrected rolling force of the rolled electrode, the rolling force correction is calculated using a PID controller. Based on the feedforward rolling force and the rolling force correction, the target rolling force of the rolled electrode is calculated. By combining the nonlinear feedforward model and PID controller fine-tuning, the feedforward rolling force calculation and rolling force correction are integrated, which improves the steady-state accuracy and dynamic response speed of rolling force control, outputs a balanced and accurate rolling force, reduces the step response time of rolling force control by 50%, and decreases the overshoot from 15% to 3%. The rolling force control method of the rolling mill in this application embodiment explicitly compensates for the nonlinear characteristics in the rolling force measurement and control channel of the rolling mill, thereby improving the response speed and steady-state accuracy of the rolling force control, outputting a balanced and accurate rolling force, improving the efficiency of electrode rolling, and ensuring the consistency of electrode thickness.

[0067] Furthermore, the rolling force control method of the roller press in this application updates the deformation resistance of the electrode sheet according to the second deviation value between the measured rolling force and the feedforward rolling force at the target time, thereby realizing online dynamic correction of the deformation resistance of the electrode sheet. This enables the rolling force control of the roller press to adapt to the material fluctuations of the electrode sheet, improves the accuracy of the rolling force control, outputs accurate rolling force, and reduces the thickness deviation of the first coil in different batches by 60%.

[0068] Corresponding to the aforementioned application function implementation method embodiments, this application also provides a rolling force control device for a roller press and corresponding embodiments.

[0069] Figure 5 This is a schematic diagram of the rolling force control device for a roller press shown in an embodiment of this application.

[0070] See Figure 5 A rolling force control device 500 for a roller press includes a feedforward module 501, a correction module 502, a calculation module 503, and a correction module 504.

[0071] The feedforward module 501 is used to determine the feedforward rolling force of the roller press for rolling the electrode sheet based on at least two preset parameters of the electrode sheet.

[0072] In one embodiment, the feedforward module 501 can calculate the feedforward rolling force of the rolled electrode based on the electrode width, deformation resistance, original thickness before rolling, target thickness after rolling, and roll radius. Combining the design parameters, process parameters, and testing equipment of the lithium-ion battery electrode, the width, deformation resistance, original thickness before rolling, and target thickness after rolling of the electrode are obtained respectively; the roll radius of the rolled electrode is obtained from the equipment nameplate or technical manual of the rolling mill, or through on-site measurement; and the feedforward rolling force of the rolled electrode is calculated based on the electrode width, deformation resistance, original thickness before rolling, target thickness after rolling, and roll radius.

[0073] The calibration module 502 is used to query a preset database based on the acquired sensor signal values ​​to determine the calibration rolling force of the rolled electrode sheet.

[0074] In one embodiment, when rolling the electrode sheet in a roller press, the correction module 502 can measure the rolling force of the roller press in real time through a pressure sensor, obtain the real-time output value of the pressure sensor, and obtain the output value range of the real-time output value by querying a piecewise linear interpolation lookup table (for example, the output value range is between 20%FS and 30%FS). Based on the output value range of the real-time output value, the output values ​​corresponding to the start and end points of the output value range, as well as the standard rolling forces corresponding to the start and end points of the output value range, are obtained respectively. Based on the real-time output value of the pressure sensor, the output values ​​corresponding to the start and end points of the output value range, and the standard rolling forces corresponding to the start and end points of the output value range, the correction rolling force of the rolled electrode sheet is calculated in real time.

[0075] The calculation module 503 is used to input the first deviation value between the feedforward rolling force determined by the feedforward module 501 and the correction rolling force determined by the correction module 502 into the PID controller to obtain the rolling force correction amount output by the PID controller.

[0076] In one embodiment, the calculation module 503 can calculate a first deviation value between the feedforward rolling force and the corrected rolling force of the rolled electrode sheet based on the feedforward rolling force and the corrected rolling force of the rolled electrode sheet; input the first deviation value into the PID controller to obtain the rolling force correction amount output by the PID controller.

[0077] The correction module 504 is used to determine the target rolling force of the rolled electrode based on the feedforward rolling force determined by the feedforward module 501 and the rolling force correction amount calculated by the calculation module 503, so as to output the rolling force control command according to the target rolling force.

[0078] In one embodiment, the correction module 504 can calculate the target rolling force of the rolled electrode in real time based on the feedforward rolling force and the rolling force correction amount calculated in real time, and input the target rolling force of the rolled electrode into the rolling mill servo valve; the rolling mill servo valve outputs the target rolling force control command in real time based on the target rolling force.

[0079] The technical solution of this application embodiment calculates the corrected rolling force of the rolled electrode sheet by looking up a table using piecewise linear interpolation based on the real-time output value of the pressure sensor; calculates the rolling force correction amount based on the first deviation between the feedforward rolling force and the corrected rolling force of the rolled electrode sheet; and calculates the target rolling force of the rolled electrode sheet based on the feedforward rolling force and the rolling force correction amount. By combining the feedforward rolling force calculation with the rolling force correction, the steady-state accuracy of the rolling force control of the rolling mill can be improved, resulting in a balanced and accurate rolling force output. This also improves the dynamic response speed of the rolling force control, reducing the response time of the rolling force control from 0.8s to 0.4s, the overshoot from 18% to 4%, and the steady-state error from ±2.3%FS to ±0.8%FS. The step response time of the rolling force control is reduced by 50%, and the overshoot is reduced from 15% to 3%. The rolling force control method of the roller press in this application can improve the steady-state accuracy of the rolling force control of the roller press, output a balanced and accurate rolling force, improve the dynamic response speed of the rolling force control, improve the efficiency of the electrode rolling, and ensure the consistency of the electrode thickness.

[0080] Figure 6 This is a schematic diagram of the rolling force control system of the roller press shown in the embodiment of this application.

[0081] See Figure 6 A rolling force control system 600 for a roller press includes a rolling force measurement unit 601, a thickness detection unit 602, an execution unit 603, and a rolling force control device 500 for the roller press.

[0082] Figure 7 This is a partial structural schematic diagram of the rolling force control system of the roller press shown in the embodiments of this application.

[0083] See Figure 6 and Figure 7 The rolling force measuring unit 601 may include a left pressure sensor (6011) and a right pressure sensor (6012) between the upper roll (611) and the lower roll (612). The rolling force measuring unit 601 can measure the rolling force of the rolled electrode through the left pressure sensor (6011) and / or the right pressure sensor (6012).

[0084] The thickness detection unit 602 may include a laser thickness gauge 6021 at the roller pressing exit. The thickness detection unit 602 can measure the thickness of the electrode before and after roller pressing using the laser thickness gauge 6021.

[0085] The rolling force control device 500 (not shown) of the rolling mill executes the rolling force control method of the rolling mill according to the embodiment of this application, outputs the target rolling force, and outputs the target rolling force to the execution unit 603.

[0086] The execution unit 603 may include a left servo valve (6031) and a right servo valve (6032). The execution unit 603 may output a rolling force control command at a target time based on the target rolling force input by the rolling force control device 500 of the roll mill, through the left servo valve (6031) and / or the right servo valve (6032).

[0087] Furthermore, this application embodiment also provides a roller press, which includes the roller press rolling force control device 500 or the roller press rolling force control system 600 described above.

[0088] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated further here.

[0089] Figure 8 This is a schematic diagram of the structure of an electronic device shown in an embodiment of this application.

[0090] See Figure 8 The electronic device 1000 includes a memory 1010 and a processor 1020.

[0091] The processor 1020 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0092] Memory 1010 may include various types of storage units, such as system memory, read-only memory (ROM), and permanent storage devices. ROM may store static data or instructions required by processor 1020 or other modules of the computer. Permanent storage devices may be read-write storage devices. Permanent storage devices may be non-volatile storage devices that retain stored instructions and data even when the computer is powered off. In some embodiments, permanent storage devices use mass storage devices (e.g., magnetic or optical disks, flash memory) as permanent storage devices. In other embodiments, permanent storage devices may be removable storage devices (e.g., floppy disks, optical drives). System memory may be a read-write storage device or a volatile read-write storage device, such as dynamic random access memory. System memory may store some or all of the instructions and data required by the processor during operation. Furthermore, memory 1010 may include any combination of computer-readable storage media, including various types of semiconductor memory chips (e.g., DRAM, SRAM, SDRAM, flash memory, programmable read-only memory), and disks and / or optical disks may also be used. In some embodiments, memory 1010 may include a removable storage device that is readable and / or writable, such as a laser disc (CD), a read-only digital multifunction optical disc (e.g., DVD-ROM, dual-layer DVD-ROM), a read-only Blu-ray disc, an ultra-high density optical disc, a flash memory card (e.g., SD card, mini SD card, Micro-SD card, etc.), a magnetic floppy disk, etc. Computer-readable storage media do not contain carrier waves or transient electronic signals transmitted wirelessly or via wired connections.

[0093] The memory 1010 stores executable code, which, when processed by the processor 1020, can cause the processor 1020 to execute part or all of the methods described above.

[0094] The method according to this application can also be implemented as a computer program or computer program product, which includes computer program code instructions for performing some or all of the steps in the method described above.

[0095] Alternatively, this application may also be implemented as a computer-readable storage medium (or a non-transitory machine-readable storage medium or a machine-readable storage medium) storing executable code (or a computer program or computer instruction code) that, when executed by a processor of a roll mill rolling force control device (roll mill rolling force control system, roll mill, electronic equipment, or server, etc.), causes the processor to perform some or all of the steps of the methods described above according to this application.

[0096] This application also provides a computer program product, which includes computer instructions that, when executed by a processor, implement the method described above.

[0097] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method of roll force control for a roll press, characterized by, include: The feedforward rolling force for rolling the electrode is determined by the roller press based on at least two preset parameters of the electrode. The corrective rolling force for rolling the electrode sheet is determined by querying a preset database based on the acquired sensor signal values. The first deviation value between the feedforward rolling force and the corrected rolling force is input into the PID controller to obtain the rolling force correction amount output by the PID controller; Based on the feedforward rolling force and the rolling force correction, a target rolling force is determined for rolling the electrode sheet, and a rolling force control command is output based on the target rolling force.

2. The method of claim 1, wherein, The step of querying a preset database based on the acquired sensor signal values ​​to determine the corrective rolling force for rolling the electrode sheet includes: Based on the real-time output value of the pressure sensor, the output value range in which the real-time output value is located, the standard rolling force corresponding to the start point of the output value range, and the standard rolling force corresponding to the end point of the output value range are obtained by querying the preset database. The corrected rolling force for rolling the electrode sheet is calculated based on the real-time output value, the output value corresponding to the start point of the output value interval and the standard rolling force, and the output value corresponding to the end point of the output value interval and the standard rolling force.

3. The method of claim 2, wherein, The preset database includes a piecewise linear interpolation lookup table, which is pre-established in the following manner: The full scale of the pressure sensor is evenly segmented to obtain I calibration pressure points within the full scale, where I is a positive integer greater than 2. Based on the original output value of the pressure sensor at each of the I calibrated pressure points and the I standard rolling forces corresponding to each of the I calibrated pressure points, a linear correspondence between the original output value of the pressure sensor and the standard rolling forces is determined, and the piecewise linear interpolation lookup table is established.

4. The method according to claim 3, characterized in that, The step of calculating the corrected rolling force for rolling the electrode sheet based on the real-time output value, the output value corresponding to the start point of the output value interval and the standard rolling force, and the output value corresponding to the end point of the output value interval and the standard rolling force includes: When the real-time output value U_raw∈[U_raw_i, U_raw_{i+1}], the standard rolling force F_std_i corresponding to the starting point U_raw_i of the output value interval and the standard rolling force F_std_{i+1} corresponding to the ending point U_raw_{i+1} of the output value interval are obtained, and the corrected rolling force for rolling the electrode sheet is calculated using the following formula. ,in, ， U_raw_i is the original output value of the pressure sensor at the i-th calibration pressure point among the I calibration pressure points, and U_raw_{i+1} is the original output value of the pressure sensor at the (i+1)-th calibration pressure point among the I calibration pressure points.

5. The method according to claim 1, characterized in that, The step of inputting the first deviation value between the feedforward rolling force and the corrected rolling force into the PID controller to obtain the rolling force correction amount output by the PID controller includes: Obtain the outer ring correction amount of the rolled electrode sheet; The feedforward rolling force is corrected using the outer ring correction amount to obtain the corrected feedforward rolling force; The first deviation value between the corrected feedforward rolling force and the corrected rolling force is input into the PID controller to obtain the rolling force correction amount output by the PID controller.

6. The method according to claim 1, characterized in that, The step of determining the feedforward rolling force for rolling the electrode sheet using a roller press based on at least two preset parameters of the electrode sheet includes: The feedforward rolling force for rolling the electrode sheet is calculated based on the width, deformation resistance, original thickness before rolling, and target thickness after rolling.

7. The method according to claim 6, characterized in that, The method further includes: Based on the second deviation between the measured rolling force at the target time and the feedforward rolling force, the deformation resistance is updated using a single-parameter recursive least squares method; or, Based on the second deviation between the measured rolling force at the target time and the feedforward rolling force, a PI controller is used to update the deformation resistance.

8. A rolling force control device for a roller press, characterized in that, include: The feedforward module is used to determine the feedforward rolling force of the roller press for rolling the electrode sheet based on at least two preset parameters of the electrode sheet; The calibration module is used to query a preset database based on the acquired sensor signal values ​​to determine the calibration rolling force for rolling the electrode sheet; The calculation module is used to input the first deviation value between the feedforward rolling force determined by the feedforward module and the correction rolling force determined by the correction module into the PID controller to obtain the rolling force correction amount output by the PID controller; The correction module is used to determine the target rolling force for rolling the electrode sheet based on the feedforward rolling force determined by the feedforward module and the rolling force correction amount calculated by the calculation module, so as to output a rolling force control command based on the target rolling force.

9. The apparatus according to claim 8, characterized in that, The device further includes: The update module is used to update the deformation resistance of the electrode sheet using a single-parameter recursive least squares method based on the second deviation value between the measured rolling force at the target time and the feedforward rolling force determined by the feedforward module; or, The update module is used to update the deformation resistance of the electrode sheet using a PI controller based on the second deviation value between the measured rolling force at the target time and the feedforward rolling force determined by the feedforward module.

10. A roller press, characterized in that, Includes the rolling force control device for a roller press as described in claim 8 or 9.

Images