A lithium battery restraint clamp device and method

Abstract

This invention discloses a lithium battery restraint fixture device and method, belonging to the field of lithium battery manufacturing equipment and control technology. The device includes: S1, providing a lithium battery clamping device comprising a servo drive, a lead screw drive, and a flexible restraint end, wherein the servo drive end moves vertically; S2, constructing a system physical model during servo no-load operation, injecting white noise to lock the first-order mechanical resonant frequency; S3, low-speed feeding of the end and injection of excitation, monitoring current energy through a bandpass filter, and determining the contact zero point based on amplitude step attenuation; S4, calculating the actual pressure during formation based on model decoupling, and generating a high-frequency micro-motion signal to adjust the pressure plate position when deviating from the set value. The virtual measurement technology of this invention eliminates the cost of external sensors and their associated circuits, and the algorithm has parameter calibration capabilities, enabling it to adapt to the aging of the mechanical structure over time, ensuring the transparency and consistency of pressure control throughout its entire lifespan.

Description

Technical Field

[0001] This invention relates to the field of lithium battery manufacturing equipment and control, specifically to a lithium battery restraint fixture device and method. Background Technology

[0002] Currently, during the lithium battery formation process, a clamping fixture is typically used to apply constant external pressure to the battery to ensure good contact at the internal interfaces and consistent gas discharge. Existing lithium battery clamping fixtures mainly employ a mechanical support frame combined with a servo drive unit and a lead screw transmission mechanism to clamp and pressurize the battery. To achieve precise monitoring and closed-loop adjustment of the pressure applied to the battery surface, the mainstream technical solution is to install an external pressure sensor in series along the force transmission link of the clamp, such as at the drive end or the support base plate. The force signal fed back in real time by this physical sensor is used for closed-loop control of the system, thereby ensuring that the pressure environment during the formation process meets process standards.

[0003] However, with the increasing demands for equipment integration, cost control, and long-term operational stability in lithium battery production, pressure control systems based on single frequencies or relying on external physical sensors have revealed some problems or weaknesses in practical applications. First, the introduction of external pressure sensors directly increases the hardware cost and installation space requirements, increasing structural complexity. Second, during long-term, high-frequency industrial operation, mechanical transmission structures inevitably experience wear, increased clearance, and changes in frictional characteristics. When minimal pressure compensation for battery expansion or low-speed motion control is required, these nonlinear mechanical factors, such as large static friction and transmission clearance dead zones, often lead to pressure control response lag, decreased control accuracy over time, and creeping or jumping phenomena during motion. These factors make it difficult to maintain high-consistency pressure control performance over the long term without frequent calibration, necessitating improvement.

[0004] The information disclosed in the background section above is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a lithium battery restraint clamp device and method to solve the problems mentioned in the background art. The technical solution of this invention is as follows:

[0006] A method for controlling a lithium battery restraint clamp includes:

[0007] S1. A lithium battery restraint clamp device is provided. The device includes a basic support frame, a servo drive unit, a lead screw transmission mechanism, and a flexible restraint end containing a floating pressure plate and an elastic coupling component. The servo drive unit is used to drive the flexible restraint end to move vertically.

[0008] S2. Control the servo drive unit to run under no-load to construct a system physical model including gravity, friction, inertia and backlash dead zone, and inject white noise excitation signal to lock the first-order mechanical resonance frequency of the system.

[0009] S3. Control the flexible restraint end to feed at low speed and inject excitation, and use a bandpass filter centered on the resonant frequency to monitor the current energy amplitude. When the amplitude decreases abruptly, it is determined to be a contact zero point.

[0010] S4. During the formation process, signals are collected and the actual pressure value is calculated based on the physical model of the system. When the pressure value deviates from the set value, a high-frequency micro-motion signal is generated and superimposed on the position command to drive the servo drive unit to adjust the position of the floating pressure plate.

[0011] Preferably, the generation of the high-frequency micro-motion signal in step S4 specifically includes:

[0012] The amplitude of the high-frequency micro-motion signal is configured to be less than the pulse equivalent value of the tooth backlash dead zone, and the frequency of the high-frequency micro-motion signal is configured to be higher than the response bandwidth of the system. The high-frequency micro-motion signals are superimposed to force the lead screw drive mechanism to remain dynamic at the micro level so as to convert static friction into dynamic friction.

[0013] Preferably, the step S4, which involves decoupling and calculating the actual pressure value applied to the battery based on the system physical model, includes:

[0014] The total electromagnetic torque of the servo drive unit is read, the torque component of gravity is subtracted, the friction torque corresponding to the Coulomb friction torque and viscous friction coefficient obtained from the table based on the current speed is subtracted, and the dynamic inertial torque generated by angular acceleration is subtracted. It is then determined whether the current motor is at the reverse zero crossing point of the speed and whether the change in position is within the preset dead zone range of the mechanical transmission chain backlash. If yes, the effective load torque is forcibly set to zero; otherwise, the effective load torque is obtained.

[0015] Based on the lead parameters and mechanical transmission efficiency of the lead screw drive mechanism, the effective load torque is linearly converted into the actual pressure value.

[0016] Preferably, step S4, which involves driving the servo drive unit to adjust the position of the floating pressure plate, includes:

[0017] Based on the characteristics of Hooke's Law of the elastic coupling component, the pressure deviation that needs to be unloaded is converted into a corresponding displacement compensation amount, and the floating pressure plate is controlled to perform a retraction action.

[0018] Preferably, step S2, before constructing the system physical model, includes:

[0019] Monitor the variance of the current signal of the servo drive unit when it is running at low speed. When the current signal shows low-frequency large-amplitude oscillations that characterize viscous sliding, record the current speed value as the critical crawling speed threshold.

[0020] A lithium battery restraint clamp device, comprising:

[0021] The basic load-bearing frame includes a load-bearing base plate and portal columns vertically welded to both sides of the load-bearing base plate;

[0022] A servo drive unit is vertically mounted on the top of the gantry column;

[0023] A lead screw drive mechanism, connected to the output end of the servo drive unit, includes a ball screw and a drive nut seat sleeved on the ball screw;

[0024] A flexible restraint end is disposed below the drive nut seat, and the flexible restraint end includes a floating pressure plate, an elastic coupling component, and a guide optical axis;

[0025] A controller is connected to the servo drive unit, and the controller is configured to execute the control method of the lithium battery restraint clamp device.

[0026] Preferably, the elastic coupling component is disposed between the bottom surface of the drive nut seat and the top surface of the floating pressure plate, the bottom end of the guide optical axis is vertically fixed to the upper surface of the floating pressure plate, and the guide optical axis passes upward into the guide holes on both sides of the drive nut seat, restricting the floating pressure plate to only move relative to the drive nut seat in the vertical direction.

[0027] Preferably, a rigid coupling is provided between the servo drive unit and the lead screw transmission mechanism, and the rigid coupling adopts a zero-backlash diaphragm structure.

[0028] Preferably, the surface of the supporting base plate is provided with a limiting groove for positioning the bottom of the battery.

[0029] Preferably, a controller is connected to the servo drive unit, the controller being used to collect the current and position signals of the servo motor and run the load observer algorithm.

[0030] This invention provides an improved lithium battery restraint clamp device and method, which, compared with the prior art, has the following improvements and advantages:

[0031] 1. This invention constructs a system physical model that includes gravity, friction, and inertial forces, and uses a servo drive unit as a sensing mechanism to directly decouple the real pressure value from the current signal. This virtual measurement technology eliminates the cost of external sensors and their associated circuits, and the algorithm has parameter calibration functions, which can adapt to the aging of mechanical structures over time, ensuring the transparency and consistency of pressure control throughout the entire life cycle.

[0032] 2. During the pressure maintenance phase, this invention generates a high-frequency micro-motion signal with an amplitude smaller than the mechanical dead zone and a frequency higher than the response bandwidth, which is superimposed on the drive command. This mechanism forces the lead screw drive mechanism to remain dynamic at the micro level, transforming the unstable static friction between the contact surfaces into a smaller and more stable dynamic friction, including Coulomb friction and viscous friction components. This significantly reduces the resistance threshold for the system to initiate micro-motions, enabling the floating pressure plate to respond sensitively and without hysteresis to extremely small deviations in battery expansion pressure, much like biological respiration. Because the threshold effect of static friction is eliminated, the system's sensitivity to small pressure changes is no longer limited by the dead zone caused by mechanical crawling, thus enabling it to actively compensate for micro-deformation of the battery in real time.

[0033] 3. This invention locks the first-order mechanical resonant frequency of the system by injecting white noise, thereby limiting the amplitude of the white noise excitation signal to a value equal to or greater than the rated torque of the servo motor. Within a certain range, to prevent excessive excitation from damaging the mechanical structure, a bandpass filter is used to monitor the energy amplitude at that frequency. When the flexible restraint end contacts the battery, the boundary conditions of the mechanical system change, causing a step change in the resonant energy. This is because at the instant of contact with the battery, the boundary conditions of the mechanical system change from a free end to a simply supported end, and the natural frequency of the system drifts. This makes the narrowband filter, which was originally aligned with the no-load resonant frequency, unable to pass the new vibration energy, resulting in a sharp drop in amplitude. This physical contact detection method based on frequency domain characteristics has a higher signal-to-noise ratio and anti-interference capability compared to the current threshold determination in the time domain, ensuring the accuracy of the initial position calibration.

[0034] 4. This invention incorporates a flexible restraint end that engages with the guide optical axis. The guide optical axis strictly restricts the floating pressure plate to move only in the vertical direction, locking the horizontal and rotational degrees of freedom and ensuring that the elastic element is always in a vertically compressed state. This design not only guarantees the linearity of Hooke's Law calculations but also eliminates lateral slippage and transmission backlash through physical limiting grooves and zero-backlash couplings, thereby ensuring the boundary conditions of the control algorithm at the hardware level and achieving high-fidelity pressure inversion. Attached Figure Description

[0035] The present invention will be further explained below with reference to the accompanying drawings and embodiments:

[0036] Figure 1 This is a schematic diagram of the overall external structure of the device;

[0037] Figure 2 This is a schematic diagram of the gantry column and its overall connection structure;

[0038] Figure 3 This is a schematic diagram of a ball screw and its connection structure;

[0039] Figure 4 This is a schematic diagram of the process flow of the method of the present invention.

[0040] In the diagram: 100, basic load-bearing frame; 110, load-bearing base plate; 120, gantry column; 200, servo drive unit; 210, servo motor; 220, rigid coupling; 300, screw drive mechanism; 310, ball screw; 320, drive nut seat; 400, flexible restraint end; 410, floating pressure plate; 420, elastic coupling assembly; 430, guide optical axis. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0042] Example 1:

[0043] Please see Figures 1-4 The present invention provides a control method for a lithium battery restraint clamp device, comprising:

[0044] S1. A lithium battery restraint clamp device is provided. The device includes a basic support frame 100, a servo drive unit 200, a lead screw transmission mechanism 300, and a flexible restraint end 400 containing a floating pressure plate 410 and an elastic coupling component 420. The servo drive unit 200 is used to drive the flexible restraint end 400 to move vertically.

[0045] S2. Control the servo drive unit 200 to run under no-load conditions to construct a system physical model including gravity, friction, inertia and backlash dead zone, and inject white noise excitation signal to lock the first-order mechanical resonance frequency of the system.

[0046] S3. Control the flexible restraint end 400 to feed at low speed and inject excitation, and use a bandpass filter centered on the resonant frequency to monitor the current energy amplitude. When the amplitude decreases abruptly, it is determined to be a contact zero point.

[0047] S4. During the formation process, signals are collected and the actual pressure value is calculated based on the physical model of the system. When the pressure value deviates from the set value, a high-frequency micro-motion signal is generated and superimposed on the position command to drive the servo drive unit 200 to adjust the position of the floating pressure plate 410.

[0048] In this embodiment, a control method for a lithium battery restraint fixture device addresses the problem that existing battery formation fixtures often rely on externally installed pressure sensors for closed-loop control. This not only increases hardware costs and installation space requirements but is also susceptible to interference from changes in gaps, friction, and stiffness of the mechanical structure due to long-term operation, leading to a decrease in pressure control accuracy over time.

[0049] This control method constructs a system physical model, where the servo drive unit 200, specifically, for example, a permanent magnet synchronous motor with low cogging torque, serves not only as an actuator but also as a sensing mechanism. In step S1, the basic mechanical architecture is built, and the rotary motion is converted into linear motion using the lead screw transmission mechanism 300, with the necessary compliance provided by the elastic coupling component 420, specifically, for example, a mold spring or disc spring assembly.

[0050] In step S2, the physical characteristics of the mechanical system are learned through a specific motion sequence, including full-stroke reciprocating motion and micro-amplitude switching. These characteristics include gravity, friction, and mechanical clearance. The parameter identification logic for the friction model is as follows: the controller drives the motor to perform uniform motion at constant speeds with different gradients. During the uniform speed phase, the inertial torque is zero, and the average torque at different speed points is recorded.

[0051] Through linear regression analysis, the torque-speed curve was fitted as follows: The form in which the intercept The coefficient of friction, B, is calibrated as the Coulomb friction torque, and the slope B is calibrated as the viscous friction coefficient. The calibration logic for the system's moment of inertia is as follows: the drive motor performs high-dynamic acceleration and deceleration motion under no-load conditions, and the torque and angular acceleration signals are collected and then calibrated using a linear fitting formula. Identify the system's moment of inertia Therefore, these non-battery reaction force interference terms are eliminated in subsequent calculations. The specific logic for locking the first-order mechanical resonance frequency is as follows: the controller collects the motor speed feedback signal after injecting white noise, and uses the fast Fourier transform algorithm to convert the time-domain signal into a frequency-domain signal; the peak point with the largest amplitude gain is searched in the frequency domain spectrum, and the frequency corresponding to this peak point is identified as the first-order mechanical resonance frequency of the system, and the energy amplitude... The calculation uses the root mean square algorithm within a sliding time window, and the calculation formula is as follows:

[0052]

[0053] in, The duration of the sliding window. This is the current signal after bandpass filtering; this frequency point reflects the sensitivity of the mechanical structure to specific frequency excitation and is the core parameter of the subsequent contact detection filter.

[0054] The first-order mechanical resonance frequency characterizes the inherent vibration characteristics of a mechanical system in a free state. When the flexible restraint end 400 contacts the battery surface, the boundary conditions of the system change, which is equivalent to adding a new constraint at the end of the cantilever beam. This will cause a sudden change in the equivalent stiffness of the system, which in turn causes the resonance frequency point to drift and the energy amplitude of the original resonance point to decrease.

[0055] In step S3, the contact zero point is identified using the principle of mechanical resonance, avoiding misjudgments caused by low signal-to-noise ratio at low speeds when relying solely on the current threshold. In step S4, the actual pressure acting on the battery is obtained through real-time decoupling calculations. When a pressure deviation is detected, a high-frequency micro-motion signal is introduced to eliminate the influence of static friction, allowing the mechanical structure to adapt to the battery's expansion like biological respiration, maintaining a constant formation pressure environment. This method improves the transparency and response speed of pressure control without adding external sensors.

[0056] The generation of high-frequency micro-motion signals in step S4 specifically includes:

[0057] The amplitude of the high-frequency micro-motion signal is less than the pulse equivalent value of the dead zone of the backlash in the mechanical transmission chain, and the frequency of the high-frequency micro-motion signal is higher than the response bandwidth of the system. The high-frequency micro-motion signals are superimposed, forcing the lead screw transmission mechanism 300 to remain dynamic at the micro level in order to convert static friction into dynamic friction.

[0058] In this embodiment, the process of generating a high-frequency micro-motion signal aims to address the problem of nonlinear and large static friction force in mechanical transmission, which often leads to crawling or response lag during minor pressure adjustments. A controller, specifically a programmable logic controller (PLC) or industrial computer (IPC) with motion control functionality, generates a jitter signal with specific characteristics. The amplitude of this signal is configured to be less than the pulse equivalent value of the mechanical transmission chain backlash dead zone to ensure that this high-frequency jitter is consumed only within the internal gaps of the mechanical transmission chain and does not manifest as macroscopic displacement jitter on the floating pressure plate 410, thus not affecting the stable pressure applied to the battery. Although the amplitude of this high-frequency micro-motion signal is limited to the mechanical dead zone and does not induce macroscopic displacement, the resulting microscopic vibration is sufficient to force the contact points inside the ball screw assembly and bearings to maintain a slight relative sliding state, thereby effectively preventing the system from falling into a high-resistance static friction state.

[0059] The frequency of this signal is configured to be higher than the system's response bandwidth to utilize the low-pass filtering characteristics of the mechanical system, preventing the jitter from being completely followed by the servo system's position loop. However, at the microscopic physical level, this forces the ball screw 310, bearings, and other contact components to remain in a state of minute relative motion. Through this superposition method, the screw drive mechanism 300 remains dynamic at the microscopic level, causing the friction characteristics between the contact surfaces to change from static friction, which is large and unstable, to dynamic friction, or viscous friction, which is small and relatively stable. This change in friction significantly reduces the resistance threshold when the system initiates minute movements, enabling the floating pressure plate 410 to make a sensitive displacement response to extremely small pressure deviations, thus improving the fineness of pressure control.

[0060] The steps in S4, which involve decoupling and calculating the actual pressure applied to the battery based on the system's physical model, include:

[0061] The total electromagnetic torque of the servo drive unit is read, the torque component of gravity is subtracted, the friction torque corresponding to the Coulomb friction torque and viscous friction coefficient obtained from the table based on the current speed is subtracted, and the dynamic inertial torque generated by angular acceleration is subtracted. It is then determined whether the current motor is at the reverse zero crossing point of the speed and whether the change in position is within the preset dead zone range of the mechanical transmission chain backlash. If yes, the effective load torque is forcibly set to zero; otherwise, the effective load torque is obtained.

[0062] Based on the lead parameters and mechanical transmission efficiency of the lead screw drive mechanism 300, the effective load torque is linearly converted into the actual pressure value.

[0063] In this embodiment, the logic for calculating the actual pressure applied to the battery based on the decoupled system physical model is based on the principle of mechanical balance. The controller reads the total electromagnetic torque fed back from the internal current loop of the servo drive unit 200 in real time, which represents the total power output of the motor. However, not all of this power is applied to the battery. Part of it is consumed to overcome the gravity of the mechanical components, another part is consumed to overcome the frictional resistance during the motion, and another part is used to drive the rotor and lead screw to accelerate or decelerate and overcome inertia. Therefore, the calculation logic first subtracts the pre-calibrated torque component of gravity to eliminate the constant interference caused by vertical installation. Second, based on the current real-time rotation speed, it consults the friction force model established in the initialization stage and subtracts the corresponding Coulomb friction torque and viscous friction torque. Third, based on the real-time monitored angular acceleration, it calculates and subtracts the dynamic inertial torque. After the above layer-by-layer stripping, the remaining torque component is the effective load torque used purely to overcome the external load, i.e., the battery reaction force. Based on the physical parameters of the lead screw drive mechanism 300, namely the lead, the distance the nut moves in one revolution of the lead screw, and the mechanical transmission efficiency, the effective load torque in the rotational dimension is converted into the actual pressure value in the linear dimension using a linear formula. Specifically, the logic of this linear conversion follows the principle of screw drive, and the calculation formula is as follows:

[0064]

[0065] in, This represents the calculated actual pressure value, and its unit is Newton (N). The effective load torque obtained from the aforementioned decoupling calculation is represented by Newton-meter (N·m). Pi; The lead parameter of the ball screw 310 is the linear distance the nut moves when the screw rotates one revolution. When substituting it into the formula for calculation, its unit needs to be converted to meters (m). This is the mechanical transmission efficiency coefficient.

[0066] This calculation process enables the acquisition of high-fidelity pressure data without the need for external sensors, providing a clean feedback source for closed-loop control.

[0067] In step S4, the adjustment of the position of the floating pressure plate 410 by driving the servo drive unit 200 includes:

[0068] Based on the characteristics of Hooke's Law of the elastic coupling component 420, the pressure deviation that needs to be unloaded is converted into the corresponding displacement compensation amount, and the floating pressure plate 410 is controlled to perform a retraction action.

[0069] In this embodiment, the servo drive unit 200 adjusts the position of the floating pressure plate 410 using the linear mechanical properties of the elastic element. When the calculated actual pressure value is higher than the target set value, for example, when the battery expands due to heat causing an increase in pressure, the controller calculates the pressure deviation between the two. Since the flexible restraint end 400 is connected in series with the elastic coupling component 420, the compression of this component and the force follow Hooke's Law. Based on this law, the controller divides the pressure deviation value by the stiffness coefficient of the elastic coupling component 420, thereby accurately deriving the theoretical displacement compensation amount that the floating pressure plate 410 needs to move in the vertical direction to eliminate the pressure deviation. The calculation logic is based on the formula... conduct.

[0070] in, The displacement compensation amount that the servo motor 210 needs to perform is converted to the linear motion dimension; The pressure deviation between the current actual pressure value and the target set value; It is the equivalent stiffness coefficient of the elastic coupling component 420.

[0071] Here, The value is taken from the slope of the force-displacement curve fitted by the compression test of the elastic component during the system initialization phase. If the elastic component uses a nonlinear spring, such as a combined disc spring, then the k value is the tangential stiffness corresponding to the current pressure range, to ensure the accuracy of the breathing adjustment step size under different pressure levels. In addition, in order to eliminate the influence of stiffness decay of the elastic coupling component 420 with the increase of usage time, the controller is also configured to drive the floating pressure plate 410 to test the rigid block with a standard height during the self-check phase before each formation process. By comparing the actual current feedback with the theoretical model, the system can... The value is corrected online.

[0072] The controller instructs the servo drive unit 200 to reverse the lead screw according to the displacement compensation amount, thereby causing the floating pressure plate 410 to perform a precise retraction action. By converting the mechanical target into a kinematic target in this way, the system can quantitatively release the excess stress caused by battery expansion, achieving active and precise pressure unloading.

[0073] The steps in S2, prior to building the system's physical model, include:

[0074] The variance of the current signal of the servo drive unit 200 is monitored when it is running at low speed. When the current signal shows low-frequency large-amplitude oscillations that characterize viscous sliding, the current speed value is recorded as the critical crawling speed threshold.

[0075] In this embodiment, monitoring the variance of the current signal of the servo drive unit 200 during low-speed operation aims to define the low-speed stability boundary of the system. Before building the model, the controller drives the motor to run at an extremely low speed and gradually reduces the speed command, while simultaneously acquiring the current signal at a high frequency. In macroscopic low-speed motion, when the speed decreases to a certain level, a physical phenomenon of alternating viscosity and slippage occurs between the mechanical transmission surfaces, causing the motion to no longer be smooth but to exhibit a stepped jump.

[0076] At this time, in order to maintain motion, the motor's current signal will exhibit a distinctive low-frequency large-amplitude oscillation, statistically characterized by a sharp increase in the variance of the current signal. The specific criterion is: when the real-time monitored variance of the current signal exceeds the motor's no-load reference variance... to When the variance changes abruptly, the controller detects this moment and records the current speed command value as the critical crawling speed threshold. The significance of determining this threshold lies in providing a boundary for subsequent control strategies: when the system operating speed is below this threshold, it indicates that the system has entered an unstable region dominated by nonlinear friction, at which point compensation strategies such as high-frequency micro-motion signals must be introduced to ensure control performance; while above this threshold, conventional control can be used, thus achieving segmented, refined management.

[0077] Specifically, the critical crawling speed threshold serves as the logical judgment point for switching control strategies: when the commanded speed is less than the threshold, the controller automatically activates the high-frequency micro-motion signal injection mode and increases the current loop integral gain to enhance the ability to destroy static friction; when the commanded speed is greater than the threshold, the system switches back to the conventional position control mode to avoid unnecessary energy loss and motor heating.

[0078] Example 2:

[0079] Please see Figures 1-3 A lithium battery restraint clamp device, comprising:

[0080] The basic load-bearing frame 100 includes a load-bearing base plate 110 and gantry columns 120 vertically welded to both sides of the load-bearing base plate 110;

[0081] The servo drive unit 200 is vertically mounted on the top of the gantry column 120;

[0082] The lead screw drive mechanism 300 is connected to the output end of the servo drive unit 200, and includes a ball screw 310 and a drive nut seat 320 sleeved on the ball screw 310.

[0083] The flexible restraint end 400 is disposed below the drive nut seat 320. The flexible restraint end 400 includes a floating pressure plate 410, an elastic coupling component 420, and a guide optical axis 430.

[0084] A controller is connected to the corresponding servo drive unit, and the controller is configured to execute a control method for a lithium battery restraint clamp device.

[0085] In this embodiment, a device serves as the hardware carrier of the aforementioned control method, ensuring the physical implementation of the control algorithm through a specific structural layout. The basic support frame 100 constructs a closed-loop force circuit, where the support base plate 110, specifically, for example, a high-strength steel plate that has undergone surface grinding, provides a horizontal reference. The gantry columns 120 are welded to form a rigid gantry structure, ensuring minimal frame deformation under high pressure conditions, thereby guaranteeing the geometric accuracy of the virtual measurement. The servo drive unit 200, serving as both a power source and signal source, is vertically arranged at the top, directly driving the load. The ball screw 310 in the screw drive mechanism 300 converts rotational torque into axial thrust, while the drive nut seat 320 serves as the central hub for motion transmission. The flexible restraint end 400 is designed not only to directly contact the battery but also to convert rigid mechanical motion into elastic pressure action through its internal structure. This hierarchical hardware architecture organically combines the three functional modules of rigid support, precision transmission, and flexible contact, providing deterministic mechanical boundary conditions for the decoupled calculations based on the physical model in the control method.

[0086] The elastic coupling component 420 is disposed between the bottom surface of the drive nut seat 320 and the top surface of the floating pressure plate 410. The bottom end of the guide optical shaft 430 is vertically fixed to the upper surface of the floating pressure plate 410. The guide optical shaft 430 passes upward into the pre-set guide holes on both sides of the drive nut seat 320, restricting the floating pressure plate 410 to only move relative to the drive nut seat 320 in the vertical direction.

[0087] In this embodiment, the elastic coupling component 420 is disposed between the bottom surface of the drive nut seat 320 and the top surface of the floating pressure plate 410, forming a sandwich-like force transmission structure in space. This ensures that the driving force must pass through an elastic element, such as a rectangular mold spring, to be transmitted to the floating pressure plate 410. The guide optical shaft 430, specifically, for example, a precision optical shaft plated with hard chrome, and the guide hole, specifically, for example, a hole with an embedded oil-free bushing or linear bearing, constitute a precise single-degree-of-freedom constraint mechanism. The function of this mechanism is to strictly limit the movement trajectory of the floating pressure plate 410, so that it can only move in the vertical direction, the Z-axis, relative to the drive nut seat 320, while completely locking the horizontal direction, the X / Y axis degrees of freedom of movement, and the degrees of freedom of rotation around the axis. This constraint ensures that the elastic coupling component 420 is always in a vertically compressed state when under pressure, avoiding spring bending or off-center loading caused by lateral forces, ensuring the applicability and linearity of Hooke's law in pressure calculation, thereby improving the accuracy of pressure inversion.

[0088] A rigid coupling 220 is provided between the servo drive unit 200 and the lead screw transmission mechanism 300. The rigid coupling 220 adopts a zero backlash diaphragm structure.

[0089] In this embodiment, the rigid coupling 220 adopts a zero-backlash diaphragm structure, connecting the motor output shaft and the lead screw input shaft. The diaphragm structure utilizes the elastic deformation of the metal diaphragm to compensate for minute installation deviations, but possesses extremely high rigidity in the torsional direction. This structure is chosen to eliminate rotational backlash in the connection; in the process where the control method relies on current signals to invert the mechanical load, any transmission backlash will cause the motor current change to lag behind the actual load change, thus introducing observation errors. The zero-backlash characteristic ensures that every minute movement of the motor rotor can be transmitted to the lead screw without delay or loss, while also ensuring that load changes at the lead screw end can be fed back to the motor's current loop in real time and directly, maximizing the signal transmission fidelity of the mechanical transmission chain.

[0090] The surface of the supporting base plate 110 is provided with a limiting groove for positioning the bottom of the battery.

[0091] In this embodiment, a limiting groove for positioning the bottom of the battery is formed on the surface of the supporting base plate 110. Specifically, this limiting groove, such as a precision-milled groove or positioning step, geometrically defines the placement position of the battery. During battery formation, the battery may tend to slip laterally under pressure. The limiting groove eliminates this risk of slippage through physical blocking, ensuring that the center of the battery always coincides with the force application center axis of the lead screw drive mechanism 300. This alignment ensures the uniformity of applied pressure, preventing damage to the internal electrode sheets or failure of the pressure detection model due to eccentric force, thereby ensuring the consistency and safety of the formation process.

[0092] The controller internally stores a friction model and is configured to fit the torque-speed curve of the servo motor under no-load conditions. The mathematical form in which For the calibrated Coulomb friction torque, The calibrated coefficient of viscous friction.

[0093] In this embodiment, the controller, specifically, such as a motion controller or high-performance PLC equipped with a real-time operating system, communicates with the servo drive unit 200 via an industrial bus, such as EtherCAT or CANopen. Its function is not only to send motion commands, but more importantly, to act as a data processing terminal, frequently acquiring the q-axis current, torque component, and encoder position signal of the servo motor 210. The controller internally runs a load observer algorithm, a software-based mathematical logic that calls a preset system physical model in real time to process the acquired raw signals. Through this hardware and software connection, the controller transforms the servo motor 210 from a simple worker into an intelligent sensor, enabling the device to sense pressure and adaptively adjust without altering the mechanical structure.

[0094] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A control method of a lithium battery restraining jig device, characterized by, Comprising: S1, providing a lithium battery restraining clamp device, the device comprising a base bearing frame (100), a servo drive unit (200), a screw rod transmission mechanism (300), and a flexible restraining end (400) comprising a floating pressure plate (410) and an elastic coupling assembly (420), the servo drive unit (200) being used to drive the flexible restraining end (400) to move vertically; S2, controlling the servo drive unit (200) to run under no load to build a system physical model containing gravity, friction, inertia and gear gap dead zone, and injecting a white noise excitation signal to lock the first order mechanical resonance frequency of the system; S3, controlling the flexible restraining end (400) to feed at low speed and injecting excitation, monitoring the current energy amplitude with a band-pass filter centered on the resonance frequency, and determining the contact zero point when the amplitude has a step attenuation; S4, collecting signals during the formation process and calculating the real pressure value based on the system physical model, generating a high-frequency micro-motion signal when the pressure value deviates from the set value, superimposing the signal on the position command to drive the servo drive unit (200) to adjust the position of the floating pressure plate (410); The step S4 includes: Reading the total electromagnetic torque of the servo drive unit (200), subtracting the torque component of the gravity, subtracting the friction torque corresponding to the Coulomb friction torque and the viscous friction coefficient according to the current speed lookup table, subtracting the dynamic inertia torque generated by the angular acceleration, determining whether the current motor is at the speed reverse zero point and whether the position change is within the preset mechanical transmission chain gear gap dead zone, and if so, forcibly setting the effective load torque to zero; if not, the effective load torque is obtained; According to the pitch parameter and mechanical transmission efficiency of the screw rod transmission mechanism (300), the effective load torque is linearly converted into the real pressure value.

2. The control method of a lithium battery restraining jig device according to claim 1, characterized by, The step S4 of generating a high-frequency micro-motion signal specifically includes: Configuring the amplitude of the high-frequency micro-motion signal to be less than the pulse equivalent value of the gear gap dead zone, configuring the frequency of the high-frequency micro-motion signal to be higher than the response bandwidth of the system, and superimposing the high-frequency micro-motion signal to force the screw rod transmission mechanism (300) to remain dynamic at the micro level to convert static friction into dynamic friction.

3. The control method of a lithium battery restraining jig device according to claim 1, characterized by, The step S4 of driving the servo drive unit (200) to adjust the position of the floating pressure plate (410) includes: According to the Hooke's law characteristics of the elastic coupling assembly (420), converting the pressure deviation that needs to be unloaded into the corresponding displacement compensation, and controlling the floating pressure plate (410) to perform a retreat action.

4. The control method of a lithium battery restraining jig apparatus according to claim 1, characterized by, The step S2 includes: Monitoring the current signal variance of the servo drive unit (200) when running at low speed, and recording the current speed value as the critical crawling speed threshold when the current signal has a low-frequency large amplitude oscillation representing viscous sliding.

5. A lithium battery restraining clamp apparatus, characterized by, Comprising: The base bearing frame (100) comprises a bearing bottom plate (110) and portal columns (120) vertically welded on both sides of the bearing bottom plate (110); A servo drive unit (200) is vertically installed on the top of the portal column (120); A screw rod transmission mechanism (300) is connected to the output end of the servo drive unit (200) and includes a ball screw rod (310) and a drive nut seat (320) sleeved on the ball screw rod (310); A flexible restraint end (400) is arranged below the drive nut seat (320), and the flexible restraint end (400) includes a floating pressing plate (410), an elastic coupling assembly (420), and a guide optical axis (430); A controller is connected to the servo drive unit (200), and the controller is configured to perform the control method of the lithium battery restraint clamp device according to any one of claims 1 to 4.

6. A lithium battery containment clamp apparatus as defined in claim 5, wherein, The elastic coupling assembly (420) is arranged between the bottom surface of the drive nut seat (320) and the top surface of the floating pressing plate (410), the bottom end of the guide optical axis (430) is vertically fixed on the upper surface of the floating pressing plate (410), the guide optical axis (430) penetrates into the pre-set guide holes on both sides of the drive nut seat (320) upward, and the floating pressing plate (410) is limited to only displace relative to the drive nut seat (320) in the vertical direction.

7. A lithium battery restraining clamp apparatus as defined in claim 5, wherein, A rigid shaft coupling (220) is arranged between the servo drive unit (200) and the screw rod transmission mechanism (300), and the rigid shaft coupling (220) adopts a zero-backlash diaphragm structure.

8. A lithium battery restraining clamp apparatus as defined in claim 5, wherein, A limiting groove for positioning the bottom of the battery is arranged on the surface of the bearing bottom plate (110).

9. A lithium battery containment clamp apparatus as defined in claim 5, wherein, The controller has a friction model stored therein, and the controller is configured to fit a torque-speed curve of the servo motor in an unloaded state to a mathematical form of wherein, is a torque of the servo motor, is a calibrated Coulomb friction torque, is a calibrated viscous friction coefficient, is a rotational speed of the servo motor.

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