Virtual-real mapping new energy cell stack force position cooperative closed-loop control method

Abstract

The present application relates to the technical field of battery manufacturing control, and discloses a new energy cell stacking force-position collaborative closed-loop control method based on virtual-real mapping. In the axial compression process, the compression state is collected and combined with the cell formula to construct the actual stacking state, which is input into the virtual stacking model to obtain the virtual stacking state and the virtual-real mapping residual error; according to the current stacking stage and the stage impedance prior, the control sequence is generated from the virtual-real constraint force-position impedance diffusion control model; the stacking response is predicted through the virtual stacking model, the control sequence is corrected by combining the virtual-real mapping residual error and the stage force-position allowable envelope, and the servo compression control instruction is generated; the virtual stacking model and the control sequence are updated according to the execution state until the compression and pressure maintaining are completed. The method improves the control accuracy and stability of the cell stacking compression and pressure maintaining.

Description

Technical Field

[0001] This invention relates to the field of battery manufacturing control technology, and in particular to a closed-loop control method for the force-position coordination of new energy cell stacking based on virtual-real mapping. Background Technology

[0002] With the increasing automation of new energy battery manufacturing equipment, cell stacking equipment typically employs servo clamping mechanisms and implements closed-loop control based on sensor data such as pressure and displacement, following preset trajectories or fixed parameters. However, influenced by initial gaps, cell manufacturing deviations, and temperature variations, the cell stack exhibits nonlinear, viscoelastic, and time-varying stiffness characteristics during compression loading and unloading rebound processes. Furthermore, different stacking stages have different requirements for force-position relationships and control parameters. Existing control methods primarily rely on current sensor feedback for adjustment, making it difficult to predict subsequent force-position responses and promptly correct the control sequence based on deviations between the actual state and the virtual model. This often leads to problems such as clamping force overshoot, positional deviation, inaccurate stage switching, and insufficient pressure holding stability. Therefore, how to coordinate and constrain the force-position relationships at different stacking stages based on the actual and virtual states of the cell stack and generate rolling closed-loop control commands has become a technical problem that needs to be solved. Summary of the Invention

[0003] To address the limitations of existing cell stacking control methods in adapting to the nonlinear, viscoelastic, and time-varying stiffness characteristics of stacked structures, this invention provides a closed-loop control method for the force-position coordination of new energy cell stacking using virtual-real mapping. During the axial compression process of the cell stack, the actual stacking state is determined based on collected data, and a virtual stacking model is used to obtain the virtual stacking state and the virtual-real mapping residual. Based on the current stacking stage, the corresponding stage impedance prior is retrieved, and a control sequence is generated through a virtual-real constraint force-position impedance diffusion control model. This control sequence is then corrected using the predicted stacking response. A servo compression control command is generated based on the corrected control sequence, and the virtual stacking model and control sequence are updated based on the actual stacking state after execution. This achieves coordinated control of the axial compression force and the pressure head position, improving the control accuracy, stability, and adaptability of the cell stacking compression and pressure holding processes.

[0004] This invention provides a closed-loop control method for the force-position coordination of new energy battery cell stacking based on virtual-real mapping. The method includes the following steps:

[0005] Step A1: During the axial clamping process of the servo clamping mechanism on the current cell stack, the axial clamping force, pressure head displacement, pressure head speed and cell temperature are acquired, and the cell stacking operation state is constructed in combination with the current cell formula; the actual stacking state is determined according to the cell stacking operation state, the actual stacking state is input into the virtual stacking model to obtain the virtual stacking state corresponding to the actual stacking state, and the current virtual-real mapping residual is determined according to the difference between the actual stacking state and the virtual stacking state;

[0006] Step A2: Determine the initial contact position and target compression position based on the number of cells, initial thickness of individual cells, initial gap, and target compression displacement in the current cell formulation; determine the initial contact position difference, target compression position difference, contact force difference, and target compression force difference based on the pressure head displacement, axial clamping force, pressure head movement direction, and axial clamping force change direction in the actual stacking state; determine the current stacking stage based on the differences, pressure head movement direction, and axial clamping force change direction; construct a stage impedance prior library; determine the stage impedance prior corresponding to the current stacking stage from the stage impedance prior library based on the current cell formulation, current stacking stage, and current virtual-real mapping residual; the stage impedance prior includes the stage force-position center trajectory, stage force-position allowable envelope, axial stiffness range, axial damping range, and force-position coordination weight range, used to limit the force-position change relationship and impedance parameter change range corresponding to the current stacking stage;

[0007] Step A3: Combine the actual stacking state, virtual stacking state, current virtual-real mapping residual, and current stacking stage to form the current virtual-real stacking control state; adopt the virtual-real constraint force-potential impedance diffusion control model, and based on the current virtual-real stacking control state, generate a candidate force-potential impedance control sequence containing the target axial clamping force, indenter displacement increment, indenter velocity, axial stiffness, and axial damping at multiple subsequent control moments within the force-potential change relationship and impedance parameter change range defined by the prior stage impedance corresponding to the current stacking stage, according to the current virtual-real stacking control state.

[0008] Step A4: Using a virtual stacking model, based on the target axial clamping force, indenter displacement increment, indenter velocity, axial stiffness, and axial damping corresponding to each control moment of the candidate force potential impedance control sequence, recursively calculate the virtual axial clamping force, virtual indenter displacement, and virtual effective stiffness for each control moment; based on the current virtual-to-real mapping residual and its deviation trend, correct the virtual calculation results for each control moment to obtain the predicted axial clamping force, predicted indenter displacement, predicted effective stiffness, and predicted virtual-to-real mapping residual, and form the predicted stacking response; based on the deviation of the predicted axial clamping force relative to the stage force potential allowable envelope, the deviation of the predicted indenter displacement relative to the target compression position, the growth rate of the predicted virtual-to-real mapping residual, and the changes in axial stiffness and axial damping at adjacent control moments, correct the control quantities in the candidate force potential impedance control sequence, and use the correction results for the next update of the candidate force potential impedance control sequence; determine the candidate force potential impedance control sequence whose predicted stacking response satisfies the force potential and impedance requirements corresponding to the current stacking stage as the target force potential impedance control sequence;

[0009] Step A5: Generate servo clamping control commands based on the target force-position impedance control sequence;

[0010] Step A6: Constrain the servo clamping control command according to the displacement, speed, acceleration and axial clamping force limits of the servo clamping mechanism and send it to the servo clamping mechanism; obtain the actual stacking state after execution, update the virtual-real mapping residual and virtual stacking model, and redetermine the current stacking stage, stage impedance prior and target force-position impedance control sequence according to the update results, and continuously generate the servo clamping control command for the next control moment until the compression and pressure holding of the current cell stack is completed.

[0011] By adopting the above solution, the beneficial effects achieved by the present invention are as follows:

[0012] By combining the axial clamping force, pressure head displacement, pressure head speed, and cell temperature collected by the cell stacking equipment with the cell formula, the actual stacking state is constructed. The virtual stacking state and the virtual-real mapping residual are obtained by using the virtual stacking model. This realizes continuous mapping and online correction between the actual operating state and the virtual calculation state of the cell stack, improves the perception and prediction accuracy of the changes in axial reaction force, compressive displacement, and effective stiffness of the cell stack, solves the problem of model mismatch caused by the fixed model being difficult to adapt to changes in the number of cells, initial gap, temperature, and viscoelastic parameters, and enhances the adaptive capability of the control system to different cell formulas and different stacking conditions.

[0013] By identifying stacking stages such as feed approach, contact establishment, compression loading, pressure holding stabilization, and unloading springback, and retrieving stage impedance priors including force-position relationship, allowable envelope, axial stiffness range, axial damping range, and force-position coordination weight range based on the current stacking stage, the system achieves the limitation of force-position change relationship and impedance parameter range for different stacking stages. On this basis, the system uses a virtual and real constraint force-position impedance diffusion control model to jointly generate target axial clamping force, indenter displacement increment, indenter speed, axial stiffness, and axial damping, improving the coordinated control capability between axial clamping force and indenter position. This solves the problems of clamping force overshoot, position deviation, and unstable stage switching that are prone to occur when using fixed control parameters or single force control or position control methods, thus enhancing the safety, stability, and reliability of the cell stacking compression process.

[0014] By recursively predicting the subsequent stacking response corresponding to the candidate force-potential impedance control sequence through a virtual stacking model, and iteratively correcting the control sequence based on the stage force-potential allowable envelope, target compression position, virtual-real mapping residual, and the degree of impedance parameter change, while combining the displacement, velocity, acceleration, and axial clamping force limits of the servo clamping mechanism to implement constraints and rolling updates, a predictive control and execution feedback closed loop for multiple subsequent control moments is realized. This improves the positioning accuracy of the compression endpoint, the tracking accuracy of the target clamping force, and the pressure holding stability, solves the control lag and error accumulation problems caused by adjusting only based on the current feedback, and enhances the system's robustness to model deviation, parameter fluctuations, and external disturbances. This is beneficial to improving the compression consistency and stacking quality of different batches of battery cell stacks. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the cell stacking device and the virtual-real mapping closed-loop control structure proposed in this invention;

[0016] Figure 2 This is a schematic diagram of the cell stacking stage and the allowable force envelope of the stage proposed in this invention;

[0017] Figure 3 This is a schematic diagram illustrating the construction and calculation principle of the virtual stacking model proposed in this invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] Example 1, as Figure 1 , Figure 2 As shown, this invention provides a closed-loop control method for the force-position coordination of new energy battery cell stacking based on virtual-real mapping. This method is applied to a battery cell stacking device including a servo pressing mechanism (10), a pressure sensor (20), a displacement sensor (30), a temperature sensor (40), and a controller (60). The method includes the following steps:

[0020] Step A1: During the axial pressing of the current cell stack (50) by the servo pressing mechanism (10), the axial pressing force, pressing head displacement, pressing head speed and cell temperature are obtained by the pressure sensor (20), displacement sensor (30) and temperature sensor (40), and the cell stacking operation state is constructed in combination with the current cell formula; the actual stacking state is determined according to the cell stacking operation state, the actual stacking state is input into the virtual stacking model to obtain the virtual stacking state corresponding to the actual stacking state, and the current virtual-real mapping residual is determined according to the difference between the actual stacking state and the virtual stacking state.

[0021] The process of determining the cell stacking operation status and actual stacking status specifically includes the following:

[0022] According to the preset control cycle, the collected axial clamping force, pressure head displacement, pressure head speed and cell temperature are time-aligned, and the number of cells, initial thickness of each cell, initial gap between adjacent cells, target clamping force, target compression displacement and holding time in the current cell formula are read to form the cell stacking operation status.

[0023] Based on the axial clamping force and pressure head displacement of adjacent control cycles, the axial clamping force change rate, pressure head displacement change rate, and online equivalent stiffness are determined. The pressure head movement direction is determined based on the pressure head speed, and the axial clamping force change direction is determined based on the axial clamping force change rate. The axial clamping force, pressure head displacement, pressure head speed, cell temperature, axial clamping force change rate, pressure head displacement change rate, online equivalent stiffness, pressure head movement direction, and axial clamping force change direction are combined to form the actual stacking state.

[0024] In one specific implementation, the cell stack consists of 20 cells, and the controller performs data acquisition and status update every 0.1 seconds. The current cell formulation specifies: initial cell thickness of 10 mm; initial gap between adjacent cells of 0.1 mm; target clamping force of 12 kN; target compression displacement of 6 mm; and holding time of 30 seconds.

[0025] Assume the data collected in the previous control cycle and the current control cycle are as shown in Table 1:

[0026] Table 1

[0027] ;

[0028] Here, 102.8mm represents the position of the pressure head in the coordinate system of the servo clamping mechanism, and does not represent the thickness of the battery cell stack.

[0029] 1. Time alignment of sensor data: The controller unifies the data from each sensor to the current control time, for example, 2.5s, and obtains: Current axial clamping force: 6.4kN; Current pressure head displacement: 102.8mm; Current pressure head speed: 4mm / s; Current cell temperature: 32.0℃.

[0030] These data are then combined with the current cell formula to form a cell stacking operation.

[0031] 2. Calculate the changes in the actual stacking state:

[0032] With a control cycle of 0.1s, the axial clamping force increases from 5.6kN to 6.4kN. Therefore, the rate of change of the axial clamping force is: .

[0033] The indenter displacement increased from 102.4 mm to 102.8 mm, therefore the rate of change of indenter displacement is: .

[0034] The online equivalent stiffness is the ratio of the change in axial clamping force to the change in indenter displacement. .

[0035] Since the displacement of the pressure head increases along the pressing direction, the direction of pressure head movement is determined to be the pressing direction; since the rate of change of axial pressing force is greater than zero, the direction of change of axial pressing force is determined to be the increasing direction.

[0036] The resulting actual stacking state includes: axial clamping force 6.4kN; clamping head displacement 102.8mm; clamping head speed 4mm / s; cell temperature 32.0℃; axial clamping force change rate 8kN / s; clamping head displacement change rate 4mm / s; online equivalent stiffness 2kN / mm; clamping head movement direction is the clamping direction; axial clamping force change direction is the increasing direction.

[0037] 3. Determine the virtual stacking state and the current virtual-to-physical mapping residual:

[0038] Input the above actual stacking state into the virtual stacking model. Assume that the virtual stacking model calculates the following: virtual axial clamping force: 6.0kN; virtual indenter displacement: 102.75mm; virtual effective stiffness: 1.8kN / mm.

[0039] The differences between the actual and virtual states are as follows: force mapping deviation: 6.4 - 6.0 = 0.4 kN; displacement mapping deviation: 102.8 - 102.75 = 0.05 mm; stiffness mapping deviation: 2.0 - 1.8 = 0.2 kN / mm.

[0040] These deviations constitute the current virtual-to-real mapping residuals. Their practical meaning is that the axial clamping force and stiffness of the current cell stack are higher than the calculation results of the virtual model, indicating that this batch of cells may be stiffer than the model predicted. Subsequent control cannot continue clamping exactly according to the original virtual model; the control sequence needs to be adjusted based on these residuals.

[0041] Step A2: Determine the initial contact position and target compression position based on the number of cells, initial thickness of individual cells, initial gap, and target compression displacement in the current cell formulation; determine the initial contact position difference, target compression position difference, contact force difference, and target compression force difference based on the pressure head displacement, axial clamping force, pressure head movement direction, and axial clamping force change direction in the actual stacking state; determine the current stacking stage based on the differences, pressure head movement direction, and axial clamping force change direction; construct a stage impedance prior library; determine the stage impedance prior corresponding to the current stacking stage from the stage impedance prior library based on the current cell formulation, current stacking stage, and current virtual-real mapping residual; the stage impedance prior includes the stage force-position center trajectory, stage force-position allowable envelope, axial stiffness range, axial damping range, and force-position coordination weight range, used to limit the force-position change relationship and impedance parameter change range corresponding to the current stacking stage;

[0042] The process of determining the current stacking stage in step A2 will be further explained.

[0043] Step C1: Using the pressing surface of the bearing platform (12) of the servo pressing mechanism (10) as the position reference, determine the initial free height of the current battery cell stack based on the number of battery cells and the initial thickness of each cell in the current battery cell formula, as well as the initial gap between each adjacent battery cell; determine the position of the pressing head when the distance between the pressing surface of the pressing head (11) and the pressing surface of the bearing platform (12) is equal to the initial free height as the initial contact position, and determine the position corresponding to the pressing head after moving the pressing head from the initial contact position along the pressing direction to the target compression displacement as the target compression position; determine the position in the coordinate system of the servo pressing mechanism (10) corresponding to the pressing head displacement in the actual stacking state as the current position of the pressing head; determine the difference between the current position of the pressing head and the initial contact position as the initial contact position difference, determine the difference between the current position of the pressing head and the target compression position as the target compression position difference, determine the difference between the current axial pressing force and the preset contact force as the contact force difference, and determine the difference between the current axial pressing force and the target pressing force as the target pressing force difference;

[0044] Step C2: When the current position of the pressure head is on the feed side of the initial contact position and has not yet entered the preset contact position range based on the initial contact position, and the contact force difference is less than zero, it is determined that the current stage is the feed approach stage; when the current position of the pressure head enters or crosses the preset contact position range along the pressing direction, and the contact force difference changes from a negative value to a non-negative value along the increasing direction, it is determined that the contact establishment is completed, and the current stage is switched to the contact establishment stage.

[0045] Step C3: After contact establishment is completed, when the pressure head movement direction points to the target compression position, the axial clamping force changes in the increasing direction, and the current position of the pressure head has not yet entered the position tolerance range corresponding to the target compression position, or the axial clamping force has not yet entered the force tolerance range corresponding to the target clamping force, it is determined that the current stage is compression loading; when both the current position of the pressure head and the axial clamping force have entered the corresponding preset target tolerance range, and the absolute value of the pressure head displacement change rate and the absolute value of the axial clamping force change rate are not greater than the corresponding steady-state change rate threshold for a consecutive preset number of control cycles, it is determined that the current stage is pressure holding stabilization.

[0046] Step C4: After contact establishment is completed, when the direction of the pressure head movement is away from the target compression position and the direction of the axial clamping force change is decreasing, it is determined that the current stage is unloading and springback. When the current control cycle does not meet any stage switching condition, the stacking stage of the previous control cycle is maintained. According to the above determination results, one of the stages of feed approach stage, contact establishment stage, compression loading stage, pressure holding and stabilization stage and unloading and springback stage is marked as the current stacking stage.

[0047] Step A3: Combine the actual stacking state, virtual stacking state, current virtual-real mapping residual, and current stacking stage to form the current virtual-real stacking control state; adopt the virtual-real constraint force-potential impedance diffusion control model, and based on the current virtual-real stacking control state, generate a candidate force-potential impedance control sequence containing the target axial clamping force, indenter displacement increment, indenter velocity, axial stiffness, and axial damping at multiple subsequent control moments within the force-potential change relationship and impedance parameter change range defined by the prior stage impedance corresponding to the current stacking stage, according to the current virtual-real stacking control state.

[0048] Step A4: Using a virtual stacking model, based on the target axial clamping force, indenter displacement increment, indenter velocity, axial stiffness, and axial damping corresponding to each control moment of the candidate force potential impedance control sequence, recursively calculate the virtual axial clamping force, virtual indenter displacement, and virtual effective stiffness for each control moment; based on the current virtual-to-real mapping residual and its deviation trend, correct the virtual calculation results for each control moment to obtain the predicted axial clamping force, predicted indenter displacement, predicted effective stiffness, and predicted virtual-to-real mapping residual, and form the predicted stacking response; based on the deviation of the predicted axial clamping force relative to the stage force potential allowable envelope, the deviation of the predicted indenter displacement relative to the target compression position, the growth rate of the predicted virtual-to-real mapping residual, and the changes in axial stiffness and axial damping at adjacent control moments, correct the control quantities in the candidate force potential impedance control sequence, and use the correction results for the next update of the candidate force potential impedance control sequence; determine the candidate force potential impedance control sequence whose predicted stacking response satisfies the force potential and impedance requirements corresponding to the current stacking stage as the target force potential impedance control sequence;

[0049] Step A5: Generate servo clamping control commands based on the target force-position impedance control sequence;

[0050] Step A6: Constrain the servo clamping control command according to the displacement, speed, acceleration and axial clamping force limits of the servo clamping mechanism and send it to the servo clamping mechanism; obtain the actual stacking state after execution, update the virtual-real mapping residual and virtual stacking model, and redetermine the current stacking stage, stage impedance prior and target force-position impedance control sequence according to the update results, and continuously generate the servo clamping control command for the next control moment until the compression and pressure holding of the current cell stack is completed.

[0051] Example 2, as Figure 3 As shown, this embodiment is based on Embodiment 1 and further explains the construction and calculation process of the virtual stacking model.

[0052] Figure 3 The left side shows the actual structure of the current cell stack. Based on the number of cells and the initial thickness of each cell in the current cell formula, the cells are arranged sequentially along the axial pressing direction of the servo pressing mechanism, and the sum of the initial gaps between adjacent cells is determined as the total initial gap. After the pressure head (11) reaches the initial contact position, it continues to move along the axial pressing direction. Part of the movement of the pressure head is used to close the initial gaps between adjacent cells, and the rest is borne by the compression deformation of each cell.

[0053] Figure 3The central section shows the series model of the viscoelastic unit corresponding to the current cell stack. Each cell is equivalent to a viscoelastic unit, and based on the historical compression data and parameter calibration results corresponding to the current cell formula, the unit loading stiffness, unit viscous damping, unit springback stiffness, and unit residual deformation at the reference temperature are determined for each viscoelastic unit.

[0054] Among them, the element loading stiffness is used to characterize the degree of change of the element axial reaction force with the amount of compression during the compression loading process, the element viscous damping is used to characterize the degree of change of the element axial reaction force with the compression speed, the element rebound stiffness is used to characterize the degree of change of the element axial reaction force with the rebound displacement during the unloading process, and the element residual deformation is used to characterize the amount of deformation of the corresponding viscoelastic element that has not recovered after unloading.

[0055] For each viscoelastic element, a compression loading branch and an unloading rebound branch are set. The compression loading branch determines the axial reaction force of the viscoelastic element under compression loading state based on the compression amount, compression velocity, element loading stiffness, and element viscous damping of the corresponding viscoelastic element. The unloading rebound branch determines the axial reaction force of the viscoelastic element under unloading rebound state based on the rebound displacement, rebound velocity, element rebound stiffness, element viscous damping, and element residual deformation of the corresponding viscoelastic element.

[0056] Since the viscoelastic units are connected in series along the axial compression direction, and neglecting the difference in inertia between the viscoelastic units, each viscoelastic unit experiences the same axial reaction force, that is: ;

[0057] in, Indicates the first The axial reaction force of a viscoelastic element. This represents the axial reaction force shared by all viscoelastic units. The axial reaction forces of each viscoelastic unit are not accumulated; instead, the shared axial reaction force is used as the virtual axial clamping force of the current cell stack.

[0058] Figure 3 The right side shows the calculation process of the virtual stacking model within one control cycle. The controller takes the number of cells, initial cell thickness, cell temperature, total compression, total compression rate, and the current calculation branch as inputs to the model.

[0059] Based on the difference between the current cell temperature and the preset reference temperature, as well as the pre-calibrated temperature correction relationship, the initial thickness of each viscoelastic unit, the unit loading stiffness, the unit viscous damping, the unit rebound stiffness, and the unit residual deformation are corrected to obtain the model parameters corresponding to each viscoelastic unit at the current cell temperature.

[0060] The displacement of the pressure head (11) from the initial contact position along the axial pressing direction is determined as the total compression amount, and the speed of the pressure head along the axial pressing direction is determined as the total compression speed; when the pressure head has not yet reached the initial contact position, the total compression amount and the total compression speed are determined to be zero.

[0061] This embodiment uses a piecewise approximation method of first closing the initial gap and then compressing each viscoelastic unit to determine the gap closure amount. When the total compression amount is not greater than the total initial gap amount, the total compression amount is determined as the gap closure amount; when the total compression amount is greater than the total initial gap amount, the total initial gap amount is determined as the gap closure amount. Therefore, the gap closure amount satisfies: ;

[0062] in, Indicates the gap closure amount. This represents the total initial gap.

[0063] After determining the gap closure amount, the portion of the total compression exceeding the gap closure amount is allocated to each viscoelastic element. The sum of the gap closure amount and the deformation of each viscoelastic element, equal to the total compression amount, is defined as the displacement-deformation compatibility constraint.

[0064] ;

[0065] in, Indicates the first The deformation of a viscoelastic element. This indicates the total compression amount.

[0066] When the axial reaction force of a unit includes a damping component related to the deformation rate, the sum of the gap closing rate and the deformation rates of each viscoelastic unit is equal to the total compression rate, which is defined as the velocity-deformation compatibility constraint.

[0067] ;

[0068] in, Indicates the gap closing speed. Indicates the first The deformation rate of a viscoelastic element This represents the total compression speed; once the initial gap is fully closed, the gap closing speed is zero.

[0069] Based on the direction of the pressure head movement and the direction of the axial clamping force change in the actual stacking state, the current calculation branch is determined from the compression loading branch and the unloading springback branch. According to the current calculation branch, the axial reaction force of each viscoelastic element is calculated, and under the condition that the axial reaction force of each viscoelastic element is equal, the deformation amount and deformation rate of each viscoelastic element are solved.

[0070] The common axial reaction force obtained from the solution is determined as the virtual axial clamping force. Under the same cell temperature and calculation branch, the total compression is increased by a preset compression increment and the virtual axial clamping force is recalculated. The virtual effective stiffness is determined based on the ratio between the change in virtual axial clamping force before and after the increase and the preset compression increment.

[0071] Example 3: Based on Example 1, this example further explains the construction of the stage impedance prior library and the retrieval process of the stage impedance prior in step A2.

[0072] Step D1: Obtain the historical compaction cycles corresponding to multiple completed cell stacks, and determine the historical compaction cycles that meet the preset stacking quality requirements and compaction safety requirements as valid historical compaction cycles; divide each valid historical compaction cycle according to the cell formula, stacking stage, pressure head movement direction and axial compaction force change direction to obtain multiple stage historical trajectory groups;

[0073] Step D2: For each stage of historical trajectory group, extract the historical pressure head displacement, historical axial pressure force, and historical pressure head velocity from the corresponding effective historical clamping cycle; and determine the position corresponding to the historical pressure head displacement in the servo clamping mechanism coordinate system as the historical pressure head position; divide multiple position intervals according to the historical pressure head position, and determine the axial pressure force center value, upper boundary value, and lower boundary value corresponding to each position interval; connect the axial pressure force center values ​​corresponding to each position interval in sequence to obtain the stage force position center trajectory, and form the stage force position allowable envelope according to the axial pressure force upper boundary value and lower boundary value; determine the axial stiffness interval according to the local slope of the stage force position center trajectory, and determine the axial damping interval according to the deviation of the historical axial pressure force relative to the stage force position center trajectory and the corresponding historical pressure head velocity;

[0074] Step D3: For each stage of historical trajectory group, obtain the historical target axial clamping force and historical target compression position from the historical cell formula and historical control records associated with the corresponding effective historical clamping cycle; determine the difference between the historical axial clamping force and the historical target axial clamping force as the historical force error, and determine the difference between the historical pressure head position and the historical target compression position as the historical position error, and convert the historical force error into the historical equivalent displacement correction amount according to the corresponding axial stiffness sample; determine the force-position coordination weight interval according to the ratio between the historical equivalent displacement correction amount and the historical position error; associate the stage force-position center trajectory, stage force-position allowable envelope, axial stiffness interval, axial damping interval, and force-position coordination weight interval with the corresponding cell formula, stacking stage, pressure head movement direction, and axial clamping force change direction to form a stage impedance prior library;

[0075] Step D4: Based on the current cell formula, the current stacking stage, and the direction of pressure head movement and axial clamping force change in the actual stacking state, determine the matching basic stage impedance prior from the stage impedance prior library; adjust the matching basic stage impedance prior according to the deviation direction and degree of the virtual-real mapping residual relative to the corresponding preset residual range to obtain the stage impedance prior corresponding to the current stacking stage.

[0076] Example 4: This example is based on Example 1 and further explains the process of generating candidate potential impedance control sequences using the virtual and real constraint potential impedance diffusion control model in step A3.

[0077] Step E1: Obtain the force mapping deviation, displacement mapping deviation, stiffness mapping deviation and their corresponding deviation trends from the virtual-real mapping residuals contained in the current virtual-real stacking control state; combine the force mapping deviation, displacement mapping deviation, stiffness mapping deviation and their deviation trends with the current stacking stage, target compression position difference and target clamping force difference to form the diffusion control conditions corresponding to the current control cycle.

[0078] Step E2: Determine the direction and change mode of the indenter displacement increment within the predictive control window based on the current stacking stage, and determine the initial indenter displacement increment corresponding to each control moment based on the target compression position difference, ensuring that the cumulative value of each initial indenter displacement increment does not exceed the remaining displacement from the current indenter position to the target compression position; starting from the current indenter position, sequentially accumulate each initial indenter displacement increment according to the control moment to obtain the initial indenter position corresponding to each control moment; determine the reference target axial clamping force corresponding to each initial indenter position based on the stage force center trajectory in the stage impedance prior corresponding to the current stacking stage, and determine the center values ​​of the axial stiffness interval and axial damping interval in the stage impedance prior corresponding to the current stacking stage as the reference axial stiffness and reference axial damping, respectively, and determine the reference indenter velocity based on the ratio of the initial indenter displacement increment to the preset control cycle; arrange the reference target axial clamping force, initial indenter displacement increment, reference indenter velocity, reference axial stiffness, and reference axial damping in sequence to obtain the stage reference control sequence;

[0079] In one specific implementation, it is assumed that the current stage is compression loading, and: the current position of the pressure head is 103.2 mm; the target compression position is 106.0 mm; the target compression position difference is -2.8 mm; the control cycle is 0.1 s; and the predictive control window includes the next 4 control moments.

[0080] Therefore, the remaining displacement from the current position of the pressure head to the target compression position is: 106.0mm - 103.2mm = 2.8mm.

[0081] 1. Determine the initial head displacement increment:

[0082] Since we are currently in the compression loading phase, all initial indenter displacement increments point to the target compression position. To gradually decelerate the indenter as it approaches the target position, the following settings can be configured, as shown in Table 2:

[0083] Table 2

[0084] ;

[0085] The sum of the initial pressure head displacement increments is 2.8 mm, which does not exceed the remaining displacement from the current position to the target compression position.

[0086] 2. Determine the initial pressure head positions:

[0087] Starting from the current position of the pressure head at 103.2 mm, the displacement increments are accumulated sequentially, as shown in Table 3:

[0088] Table 3

[0089] ;

[0090] 3. Determine the axial clamping force of the reference target:

[0091] Assuming the trajectory of the force center during the compression loading phase is defined as shown in Table 4:

[0092] Table 4

[0093] ;

[0094] These pressures are then determined as the reference target axial clamping force at the corresponding control moment. This part does not directly distribute the final target clamping force of 12kN to all control moments, but rather gradually increases the reference target axial clamping force according to the process of the pressure head gradually approaching the target compression position.

[0095] The center values ​​of the axial stiffness interval and axial damping interval in the prior stage impedance corresponding to the current stacking stage are determined as the reference axial stiffness and reference axial damping, respectively. The reference indenter velocity is determined according to the ratio of the initial indenter displacement increment to the preset control period, and the stage reference control sequence is obtained, as shown in Table 5.

[0096] Table 5

[0097] .

[0098] Step E3: Generate an initial diffusion disturbance sequence corresponding to the stage reference control sequence according to the preset disturbance distribution, and superimpose the initial diffusion disturbance sequence onto the stage reference control sequence to obtain the initial force-potential impedance control sequence; in each diffusion update, determine the initial force-potential impedance control sequence or the force-potential impedance control sequence after the previous constraint as the force-potential impedance control sequence to be updated; based on the diffusion control conditions and the force-potential impedance control sequence to be updated, determine the sequence correction amount corresponding to the target axial clamping force, indenter displacement increment, indenter velocity, axial stiffness, and axial damping at each control moment within the prediction control window through the virtual and real constraint force-potential impedance diffusion control model; use the various sequence correction amounts to jointly update the force-potential impedance control sequence to be updated to obtain the current force-potential impedance control sequence; the virtual and real constraint force-potential impedance diffusion control model is: a conditional denoising diffusion sequence model deployed in the controller, used to perform multiple joint corrections on the target axial clamping force, indenter displacement increment, indenter velocity, axial stiffness, and axial damping within the prediction control window near the stage reference control sequence;

[0099] The diffusion joint update formula guided by virtual and real residuals satisfies the following in each diffusion update: [Formula omitted for brevity]

[0100] ;

[0101] in, Indicates the diffusion update sequence number. Indicates the first The force potential impedance control sequence to be updated after range conversion before the next diffusion update; Indicates the first The updated potential impedance control sequence after secondary diffusion; This represents the correction amount of the base sequence determined by the sequence denoising branch based on the force potential impedance control sequence to be updated; This represents the correction amount of the virtual and real residual sequence determined by the diffusion control conditions for the virtual and real conditional coding branches; This represents the base denoising step size coefficient corresponding to the current diffusion update; This indicates the maximum guiding coefficient for the preset virtual-real residual; This indicates the disturbance level corresponding to the current diffusion update; This indicates the maximum disturbance level corresponding to the initial diffusion disturbance;

[0102] Step E4: Starting from the current position of the pressure head, sequentially accumulate the pressure head displacement increment in the current force-potential impedance control sequence to obtain the candidate pressure head position at each control moment; restrict each candidate pressure head position to the position range of the stage force-potential allowable envelope corresponding to the current stacking stage, and correct the corresponding pressure head displacement increment according to the difference between adjacent candidate pressure head positions; constrain the target axial clamping force according to the stage force-potential allowable envelope at each candidate pressure head position, constrain the corresponding axial stiffness and axial damping according to the axial stiffness range and axial damping range, and correct the pressure head velocity according to the corrected pressure head displacement increment and the preset control cycle to obtain the constrained force-potential impedance control sequence; use the constrained force-potential impedance control sequence for the next diffusion update until the preset number of diffusion updates is reached, and determine the constrained force-potential impedance control sequence obtained after the last diffusion update as the candidate force-potential impedance control sequence.

[0103] Example 5, based on Example 1, further explains the generation process of the servo clamping control command in step A5. The candidate force-position impedance control sequence is generated using the method described in Example 4.

[0104] Step G1: Determine the force error and position error respectively based on the target axial clamping force and target indenter position at the current control moment in the target force-position impedance control sequence;

[0105] Step G2: Determine the extent to which the predicted axial clamping force exceeds the upper boundary of the stage force-position allowable envelope corresponding to the predicted indenter displacement as the predicted force overshoot, and determine the difference between the predicted indenter displacement and the target compression position as the predicted displacement error; divide the force error by the predicted effective stiffness to obtain the equivalent displacement correction with the same dimensions as the position error; determine the current force-position coordination weight within the force-position coordination weight range defined by the stage impedance prior, based on the current stacking stage, the predicted force overshoot, and the predicted displacement error;

[0106] Step G3: Use the current force-position coordination weight to fuse the equivalent displacement correction and the position correction corresponding to the position error to obtain the pressure head displacement control amount. Then, dynamically correct the pressure head displacement control amount according to the pressure head speed, axial stiffness and axial damping in the target force-position impedance control sequence to form the constrained servo clamping control command.

[0107] Step G4: Limit the amplitude of the servo clamping control command to be constrained according to the upper limit of displacement, upper limit of speed, upper limit of acceleration and upper limit of axial clamping force of the servo clamping mechanism, and generate the servo clamping control command.

[0108] The present invention and its embodiments have been described above. This description is not restrictive. The accompanying drawings are only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the spirit of the present invention, such design should fall within the protection scope of the present invention.

Claims

1. A closed-loop control method for the force-position coordination of new energy battery cell stacking based on virtual-real mapping, characterized in that, The method includes the following steps: Step A1: Construct the cell stacking operation status; determine the actual stacking status based on the cell stacking operation status, input the actual stacking status into the virtual stacking model to obtain the virtual stacking status, and determine the current virtual-real mapping residual based on the difference between the actual stacking status and the virtual stacking status; Step A2: Determine the current stacking stage; construct a stage impedance prior library, and determine the current stage impedance prior from the stage impedance prior library based on the current cell formula, the current stacking stage, and the current virtual-real mapping residual; Step A3: Combine the actual stacking state, virtual stacking state, current virtual-real mapping residual, and current stacking stage to form the current virtual-real stacking control state; use the virtual-real constraint force potential impedance diffusion control model to generate candidate force potential impedance control sequences within the force potential change relationship and impedance parameter change range that are a priori defined by impedance in the current stage. Step A4: Using a virtual stacking model, correct the control quantities in the candidate potential impedance control sequence, and use the correction results for the next update of the candidate potential impedance control sequence to determine the target potential impedance control sequence; Step A5: Generate servo clamping control commands based on the target force-position impedance control sequence; Step A6: Constrain the servo clamping control command and send it to the servo clamping mechanism to execute the command and complete the compression and pressure holding of the current cell stack.

2. The new energy cell stacking force-position coordinated closed-loop control method based on virtual-real mapping according to claim 1, characterized in that, The current stacking phase includes the feed approach phase, contact establishment phase, compression loading phase, pressure holding and stabilization phase, and unloading and springback phase.

3. The new energy cell stacking force-position coordinated closed-loop control method based on virtual-real mapping according to claim 1, characterized in that, The process of constructing the stage impedance prior library includes the following steps: Step S1: Obtain the historical compaction cycles corresponding to multiple completed cell stacks and determine the effective historical compaction cycles; divide each effective historical compaction cycle to obtain multiple stage historical trajectory groups; Step S2: For each stage of historical trajectory group, extract the historical pressure head displacement, historical axial pressure force, and historical pressure head velocity from the corresponding effective historical clamping cycle; determine the historical pressure head position in the servo clamping mechanism coordinate system; divide multiple position intervals according to the historical pressure head position, and determine the axial pressure force center value, upper boundary value, and lower boundary value corresponding to each position interval; connect the axial pressure force center values ​​corresponding to each position interval in sequence to obtain the stage force position center trajectory, and form the stage force position allowable envelope according to the upper boundary value and lower boundary value of the axial pressure force; determine the axial stiffness interval according to the local slope of the stage force position center trajectory, and determine the axial damping interval according to the deviation of the historical axial pressure force relative to the stage force position center trajectory and the corresponding historical pressure head velocity; Step S3: For each stage of historical trajectory group, obtain the historical target axial clamping force and historical target compression position from the historical cell formula and historical control records associated with the corresponding effective historical clamping cycle; determine the difference between the historical axial clamping force and the historical target axial clamping force as the historical force error, and determine the difference between the historical pressure head position and the historical target compression position as the historical position error, and convert the historical force error into the historical equivalent displacement correction amount; determine the force-position coordination weight interval based on the ratio between the historical equivalent displacement correction amount and the historical position error; associate the stage force-position center trajectory, stage force-position allowable envelope, axial stiffness interval, axial damping interval, and force-position coordination weight interval with the corresponding cell formula and stacking stage to form a stage impedance prior library.

4. The new energy cell stacking force-position coordinated closed-loop control method based on virtual-real mapping according to claim 3, characterized in that, The stage impedance prior is used to define the force potential change relationship and impedance parameter change range corresponding to the current stacking stage.

5. The new energy cell stacking force-position coordinated closed-loop control method based on virtual-real mapping according to claim 2, characterized in that, The process of generating candidate potential impedance control sequences using a virtual-real constraint potential impedance diffusion control model includes the following steps: Step E1: Obtain the force mapping deviation, displacement mapping deviation, stiffness mapping deviation and their corresponding deviation trends from the virtual-real mapping residuals contained in the current virtual-real stacking control state; combine the force mapping deviation, displacement mapping deviation, stiffness mapping deviation and their deviation trends with the current stacking stage to form diffusion control conditions. Step E2: Determine the direction and change mode of the indenter displacement increment based on the current stacking stage to obtain each initial indenter displacement increment; accumulate each initial indenter displacement increment to obtain the initial indenter position; determine the reference target axial clamping force corresponding to each initial indenter position based on the stage force center trajectory in the current stage impedance prior; determine the center values ​​of the axial stiffness interval and axial damping interval in the current stage impedance prior as the reference axial stiffness and reference axial damping, respectively; and determine the reference indenter velocity based on the ratio of the initial indenter displacement increment to the preset control cycle; arrange the reference target axial clamping force, initial indenter displacement increment, reference indenter velocity, reference axial stiffness, and reference axial damping in sequence to obtain the stage reference control sequence; Step E3: Generate an initial diffusion perturbation sequence and superimpose it onto the stage reference control sequence to obtain an initial force potential impedance control sequence; in each diffusion update, the initial force potential impedance control sequence is determined as the force potential impedance control sequence to be updated; based on the diffusion control conditions and the force potential impedance control sequence to be updated, the sequence correction amount is determined through the virtual and real constraint force potential impedance diffusion control model, and a joint update is performed to obtain the current force potential impedance control sequence; Step E4: Constrain the current force potential impedance control sequence based on the stage force potential allowable envelope, axial stiffness range, and axial damping range; repeat the diffusion update and constraint to a preset number of times to obtain the candidate force potential impedance control sequence.

6. The new energy cell stacking force-position coordinated closed-loop control method based on virtual-real mapping according to claim 5, characterized in that, Step A4 specifically includes: using a virtual stacking model, recursively deriving virtual axial clamping force, virtual indenter displacement, and virtual effective stiffness according to the target axial clamping force, indenter displacement increment, indenter velocity, axial stiffness, and axial damping at each control moment of the candidate force potential impedance control sequence; correcting the virtual calculation results based on the current virtual-real mapping residual to obtain the predicted axial clamping force, predicted indenter displacement, predicted effective stiffness, and predicted virtual-real mapping residual, and forming the predicted stacking response; correcting the control quantities in the candidate force potential impedance control sequence based on the deviation of the predicted axial clamping force relative to the stage force potential allowable envelope, the deviation of the predicted indenter displacement relative to the target compression position, the growth rate of the predicted virtual-real mapping residual, and the changes in axial stiffness and axial damping at adjacent control moments, and using the correction results for the next update of the candidate force potential impedance control sequence to determine the target force potential impedance control sequence.

Images