Full-automatic restraining and un-restraining device and method for lithium battery restraining tray

Abstract

The application relates to a full-automatic restraining device and method for a lithium battery restraining tray, and belongs to the technical field of lithium battery manufacturing and testing equipment, which comprises the following steps: S1, a device containing power transmission, elastic buffering and an execution end is arranged, a driving sliding block is driven by a spring set to drive a driven sliding block; S2, an empty load scanning resistance curve, inertia compensation and hysteresis loss table are generated; S3, forward determination contact is utilized to calculate a virtual absolute zero point by using shallow compression zone data; and S4, displacement is calculated according to target force and stiffness, and the sliding block is controlled to forward theoretically by a displacement from the virtual zero point. The scheme adopts a virtual absolute zero point calibration algorithm, theoretically position coordinates when net load torque is zero are calculated through multi-point data collection and linear regression analysis in a shallow compression zone, thereby the uncertainty of a physical contact instant is avoided, a unified and accurate mechanical zero point is established, and a benchmark is provided for subsequent accurate compression.

Description

Technical Field

[0001] This invention relates to the field of lithium battery manufacturing and testing equipment, specifically to a fully automated device and method for adding and releasing restraints on a lithium battery restraint tray. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the safety and consistency of lithium batteries have become a focus of industry attention. Formation and capacity testing, as key processes in the back end of lithium battery production, are core steps in activating battery performance. The pressure accuracy and stability of the restraint tray system are crucial for ensuring the safety and performance of the battery during charging and discharging. However, in actual large-scale production, restraint equipment operates under high-frequency, high-load conditions and is subject to complex mechanical conditions, such as guide rail friction, component wear, and environmental factors, making it prone to unstable pressure control. Restraint force fluctuations are one of the main causes of decreased battery formation quality and even safety accidents. Furthermore, since restraint devices are usually integrated into automated production lines, the collected force feedback signals not only contain the force information of the battery itself but also include a large amount of mechanical transmission friction, environmental vibration, and electrical interference from the servo system, posing a significant challenge to accurately identifying the restraint state. Traditional pressure control methods mainly rely on external sensors, such as pressure sensor data, and are implemented through setting thresholds or simple feedback adjustments. However, these methods have the following limitations:

[0003] Limitations of a single data source: Although external sensors can directly feed back force values, they are susceptible to noise interference in complex industrial electromagnetic environments, and even slight deviations in the sensor's installation position can cause reading drift, resulting in limited diagnostic accuracy.

[0004] Limitations of feature extraction: Traditional feature extraction methods, such as simple threshold judgment, are difficult to capture the nonlinear contact characteristics of the pouch battery surface. For example, the surface of a pouch battery is often uneven, and traditional contact detection methods are not sensitive to soft contacts, making it difficult to accurately distinguish between mechanical friction and actual contact, thus making it difficult to determine the true zero point of contact.

[0005] Limitations of Model Performance: Existing control models often simplify elastic buffer structures to ideal linear models, resulting in insufficient utilization of their physical characteristics. In reality, elastic elements exhibit significant hysteresis during pressurization and depressurization, meaning that the applied force and unloaded force are inconsistent at the same location, and the battery body experiences stress relaxation and force decay after prolonged pressure. Existing technologies struggle to fully utilize the multi-scale changes in these physical characteristics and cannot effectively address nonlinear errors.

[0006] In recent years, internal signal monitoring technology based on servo motors has gradually become a research hotspot in the field of industrial control. By combining motor current, speed, and position signals, the operating status of the load can be reflected from both mechanical and electrical perspectives. Furthermore, utilizing electromechanical coupling characteristics for indirect force control can avoid interference from external sensors, providing richer data support for high-precision constraint.

[0007] However, relying solely on current signals results in a low signal-to-noise ratio under low-speed, high-damping conditions, and its widespread application in precision force control remains a challenge, especially in removing interference from the inherent resistance of the system.

[0008] In summary, existing technologies and conventional control models have problems such as insufficient consideration of hysteresis characteristics and stress relaxation phenomena, and ambiguous definition of contact zero point when dealing with soft-pack battery restraint operations. They are unable to fully utilize the advantages of electromechanical coupling data, and there is no research on combining high-precision indirect force control with dynamic physical characteristic compensation for fully automatic addition and release of restraints on lithium battery restraint trays.

[0009] The information disclosed in the background section 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

[0010] The purpose of this invention is to provide a fully automatic device and method for adding and releasing restraints on a lithium battery restraint tray, in order to solve the problems mentioned in the background art. The technical solution of this invention is as follows:

[0011] A fully automated method for adding and releasing restraints on a lithium battery restraint tray includes:

[0012] S1. A device including a main support frame, a power transmission chain, an elastic buffer relay structure, and an adaptive restraint execution end is provided; the power transmission chain consists of a servo drive component and a lead screw drive component, which drives the active slider in the elastic buffer relay structure, and drives the driven slider and the adaptive restraint execution end at the front end through a pre-pressed stiffness calibration spring group.

[0013] S2. Control the active slider to perform a full-stroke scan under no-load conditions, record the motor current to generate a mechanical friction resistance distribution curve and an inertia compensation coefficient, and record the bidirectional load difference of the stiffness calibration spring group to generate a bidirectional hysteresis loss mapping table.

[0014] S3. Control the active slider to move forward and calculate the net load torque. After continuous sampling exceeds the contact threshold to determine contact, collect multiple sets of position and torque data in the shallow compression zone. Calculate the coordinates where the net load torque is zero through linear regression analysis as the virtual absolute zero point position.

[0015] S4. Calculate the theoretical compression displacement based on the target restraint force and the stiffness coefficient of the stiffness calibration spring group, and control the active slider to move forward by the theoretical compression displacement from the virtual absolute zero position.

[0016] Preferably, step S4 includes:

[0017] Determine whether the current motion state is pressure loading or pressure release rebound, and find the hysteresis force difference corresponding to the current target position according to the bidirectional hysteresis loss mapping table indexed by the motion state.

[0018] The hysteresis force difference is divided by the stiffness coefficient of the stiffness calibration spring group to convert it into a displacement correction amount, and the displacement correction amount is added to the theoretical compression displacement amount.

[0019] Preferably, step S4 is followed by:

[0020] S5. During the restraint and holding phase, continuously monitor the current fluctuation of the servo drive component. When a downward trend in the current is detected, use the linear proportional relationship between the force and displacement of the stiffness calibration spring group to convert the decrease in current into the loss value of spring compression.

[0021] S6. The loss value is sent as a micro-feed command to the servo drive component to drive the motor for creep compensation.

[0022] Preferably, step S4 includes:

[0023] The current rise slope of the servo drive component relative to the displacement is monitored in real time. When the current rise slope deviates from the calibration stiffness characteristic line of the stiffness calibration spring group, emergency stop protection is triggered.

[0024] A fully automatic restraint application and release device for a lithium battery restraint tray includes:

[0025] The main support frame includes a base platform and gantry columns;

[0026] The power transmission chain includes a servo drive assembly and a lead screw drive assembly. The servo drive assembly is fixed to the base platform, and the lead screw drive assembly is connected to the output shaft of the servo drive assembly.

[0027] An elastic buffer relay structure is set on the guide rail of the base platform, including an active slider, a driven slider and a stiffness calibration spring group. The active slider is connected to the lead screw transmission assembly, the driven slider is located in front of the active slider, and the stiffness calibration spring group is set between the active slider and the driven slider.

[0028] An adaptive constraint actuator is connected to the front end of the driven slider.

[0029] Preferably, the elastic buffer relay structure further includes a limiting guide bolt, one end of which is fixed to the active slider, the rod of which passes through the stiffness calibration spring assembly and into the through hole of the driven slider, and the head of which is located in the countersunk seat at the front end of the driven slider.

[0030] When the active slider moves forward, it pushes the driven slider through the stiffness calibration spring group; when the active slider moves backward, it pulls the driven slider back to its original position through the head of the limit guide bolt.

[0031] Preferably, the adaptive restraint actuator includes a floating connecting plate and a restraint pressure head. The back of the floating connecting plate is provided with an inwardly recessed spherical bearing mounting seat. The front end of the driven slider is provided with a bearing bracket. The floating connecting plate is connected to the spherical bearing in the bearing bracket by a pin.

[0032] A pair of elastic anti-rotation pins are provided between the floating connecting plate and the driven slider.

[0033] Preferably, the surface of the restraint indenter is covered with insulating hard rubber, the hardness of which is higher than 80 Shore D.

[0034] Preferably, the servo drive assembly includes an AC servo motor with an absolute encoder, and the output shaft of the servo drive assembly is connected to the lead screw drive assembly via a plum blossom-shaped flexible coupling, wherein the plum blossom-shaped flexible coupling has a plum blossom elastomer hardness of 98A.

[0035] Compared with the prior art, the present invention has the following improvements and advantages:

[0036] 1. This solution constructs an electromechanical coupling model and utilizes the current signal of the servo motor in conjunction with the physical characteristics of the stiffness calibration spring group to replace the easily interfered external pressure sensor. By converting the target restraint force into the theoretical compression displacement and combining it with the subtraction of the mechanical friction resistance distribution curve, precise pressure control is achieved without external sensors, reducing hardware costs and improving the system's anti-interference capability. Addressing the microscopic unevenness often present on the surface of lithium batteries, especially pouch batteries, this solution employs a virtual absolute zero-point calibration algorithm. Through multi-point data acquisition and linear regression analysis in the shallow compression zone, the theoretical position coordinates when the net load torque is zero are calculated, thus avoiding the uncertainty at the moment of physical contact and establishing a unified and accurate mechanical zero point, providing a benchmark for subsequent precise compression.

[0037] 2. This solution generates a mechanical friction resistance distribution curve through no-load scanning to eliminate guide rail friction interference. It also establishes a bidirectional hysteresis loss mapping table to compensate for the force difference of the spring during pressurization and depressurization. Furthermore, addressing the force attenuation caused by stress relaxation between battery electrode layers, the solution monitors the current drop during the holding phase, reverses the spring compression loss value, and drives the motor for creep compensation, ensuring pressure constancy during long-cycle restraint. This solution introduces a slope monitoring mechanism based on a physical model. By calculating the current rise slope in real time and comparing it with the calibrated stiffness characteristic line, the system can sensitively identify abnormal stiffness changes caused by metallic foreign objects or cell bulging, thereby triggering emergency stop protection before an accident occurs, significantly improving equipment operational safety.

[0038] 3. The elastic buffer relay structure of this scheme adopts a special design that combines the limiting guide bolt with the countersunk seat, realizing flexible buffering during pressurization and forced mechanical reset during release. This design not only ensures the smoothness and measurability of the force application process, but also effectively prevents the driven slider from failing to reset due to resistance retention, thus improving the reliability of mechanical action. Attached Figure Description

[0039] The present invention will be further explained below with reference to the accompanying drawings and embodiments:

[0040] Figure 1 This is a schematic diagram of the overall external structure of the device;

[0041] Figure 2 This is a schematic diagram of the connection structure of the power transmission chain, the elastic buffer relay structure, and the adaptive constraint actuator.

[0042] Figure 3 This is a schematic diagram of the process flow of the method of the present invention.

[0043] In the diagram: 100, main support frame; 110, base platform; 120, gantry column; 200, power transmission chain; 210, servo drive assembly; 220, lead screw drive assembly; 300, elastic buffer relay structure; 310, active slider; 320, driven slider; 330, stiffness calibration spring assembly; 400, adaptive restraint actuator; 410, floating connecting plate; 420, restraint pressure head. Detailed Implementation

[0044] 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.

[0045] Example 1:

[0046] Please see Figures 1-3 This invention provides a fully automated method for adding and releasing restraints on a lithium battery restraint tray, comprising:

[0047] S1. A device comprising a main support frame 100, a power transmission chain 200, an elastic buffer relay structure 300, and an adaptive restraint execution end 400 is provided; the power transmission chain 200 is composed of a servo drive assembly 210 and a lead screw drive assembly 220, which drives the active slider 310 in the elastic buffer relay structure 300, and drives the driven slider 320 and the adaptive restraint execution end 400 at the front end through a pre-pressed stiffness calibration spring assembly 330;

[0048] S2. Control the active slider 310 to perform a full-stroke scan under no-load conditions, record the motor current to generate a mechanical friction resistance distribution curve and an inertia compensation coefficient, and record the bidirectional load difference of the stiffness calibration spring group 330 to generate a bidirectional hysteresis loss mapping table.

[0049] S3. Control the active slider 310 to move forward and calculate the net load torque. After continuous sampling exceeds the contact threshold and contact is determined, collect multiple sets of position and torque data in the shallow compression zone. Calculate the coordinates where the net load torque is zero through linear regression analysis as the virtual absolute zero point position.

[0050] S4. Calculate the theoretical compression displacement based on the target restraint force and the stiffness coefficient of the stiffness calibration spring group 330, and control the active slider 310 to move forward by the theoretical compression displacement from the virtual absolute zero position.

[0051] In this embodiment, to address the pain points of external sensors being susceptible to interference and the difficulty in determining the zero point in the prior art, this method constructs an indirect force control system based on an electromechanical coupling model.

[0052] In step S1, the physical system is built to convert force control into high-precision displacement control. The system has a pre-set current-torque-axial force conversion model, which is built based on deterministic mechanical parameters such as the torque constant of the servo motor, the lead of the lead screw drive assembly 220, and the reduction ratio, ensuring the reversible derivation between the current signal and the end thrust.

[0053] In step S2, to eliminate the system's own resistance interference, the servo drive component 210 is controlled to perform a no-load full-stroke scan. During this process, the controller controls the servo drive component 210 to move at a low and uniform speed, records the current noise floor of the entire stroke, and generates a mechanical friction resistance distribution curve, which reflects the inherent friction force of the guide rail at different positions. At the same time, based on the physical characteristics of the stiffness calibration spring group 330, the difference in force value at the same position of compression and rebound is recorded, generating a bidirectional hysteresis loss mapping table to provide a compensation benchmark for subsequent high-precision force control.

[0054] In step S3, the core is to accurately capture the contact point and calibrate the zero point. The system controls the active slider 310 to move forward, monitors the motor torque current in real time, and subtracts from it the mechanical friction resistance recorded in step S2 at the corresponding position and the dynamic inertial torque calculated based on the inertia compensation coefficient and the current real-time acceleration. ,in, This is the equivalent moment of inertia of the system converted to the motor shaft. The net load torque is obtained by taking the motor angular acceleration. To prevent misjudgment caused by guide rail oil contamination or instantaneous vibration, the system sets a contact threshold, which is set slightly higher than the maximum fluctuation peak value in the mechanical friction resistance distribution curve.

[0055] Specifically, the contact threshold is set to 1.2 to 1.5 times the mechanical friction resistance value corresponding to the position. This multiple range is based on the system signal-to-noise ratio preset. 1.2 times is the minimum safety margin to overcome the servo current noise floor, while 1.5 times is the upper limit to prevent misjudgment caused by the instantaneous change in friction force due to the rupture of the local oil film on the guide rail.

[0056] Only when the net load torque exceeds the contact threshold for three consecutive sampling cycles, for example, when the sampling frequency is 1kHz, i.e., for 3ms, is the system considered a valid physical contact to exclude transient spikes caused by a single electromagnetic interference pulse or mechanical collision. The decision logic for three consecutive sampling cycles is equivalent to a time-domain low-pass filter, which aims to filter out high-frequency electromagnetic interference signals with frequencies higher than 333Hz and transient impacts in the mechanical transmission chain to ensure the authenticity of the contact signal.

[0057] To address the nonlinearity issue in soft contacts caused by uneven surfaces of pouch cells, the system executes a virtual absolute zero-point calibration algorithm:

[0058] The slider is controlled to continue advancing slightly, allowing the stiffness calibration spring assembly 330 to enter a stable linear compression range, i.e., a shallow compression zone, while multiple sets of position coordinates are collected. With the corresponding net load torque ;

[0059] The travel range of the shallow compression zone is set to 5% to 10% of the maximum linear travel of the stiffness calibration spring assembly 330. Within this range, the controller steps in a preset micron-level increment and simultaneously collects no less than 10 sets of data points.

[0060] The system uses the least squares method to perform linear regression analysis on these data points and fits a straight line equation:

[0061]

[0062] in, Represents net load torque; Represents location coordinates; The system's equivalent stiffness slope for the current fitted interval, in units of: ; This is the intercept.

[0063] The system uses this equation to derive the calculation of the net load torque. The theoretical position coordinates corresponding to the time ;Should This is defined as a virtual absolute zero point position; the method avoids the uncertainty of the instant of physical contact through mathematical fitting and establishes a unified mechanical zero point.

[0064] In step S4, based on Hooke's law and transmission chain parameters, the target restraint force value is converted into the target pulse number of the servo motor, and the active slider 310 is controlled to feed precisely from the virtual absolute zero position, realizing sensorless precision force control.

[0065] The steps in S4 include:

[0066] Determine whether the current motion state is pressure loading or pressure release rebound, and find the hysteresis force difference corresponding to the current target position according to the bidirectional hysteresis loss mapping table of motion state index;

[0067] Divide the hysteresis force difference by the stiffness coefficient of the stiffness calibration spring group 330 to convert it into a displacement correction amount, and then add the displacement correction amount to the theoretical compression displacement amount.

[0068] In this embodiment, considering that elastic elements such as springs experience energy dissipation due to internal friction during physical compression and rebound, resulting in a hysteresis loop phenomenon, i.e., at the same position, the loading force is often greater than the unloading force. In step S4, the system identifies whether the current motion command is forward pressurization or reverse depressurization; based on this state, the system indexes the bidirectional hysteresis loss mapping table generated in step S2 to obtain the hysteresis force difference at the current target position. .

[0069] The system performs displacement compensation calculations:

[0070]

[0071] in, This is the displacement correction amount. The linear stiffness coefficient of spring assembly 330 is used to calibrate the stiffness.

[0072] The system adds the calculated displacement correction to the theoretical compression displacement and dynamically adjusts the final stopping position of the motor. This process eliminates the inherent nonlinear error of the elastic element and ensures that the actual restraint force applied to the battery remains consistent with the target value, whether during the pressurization or depressurization process.

[0073] The steps following S4 include:

[0074] S5. During the restraint and holding phase, continuously monitor the current fluctuation of the servo drive component 210. When a downward trend in the current is detected, use the linear proportional relationship between the force and displacement of the stiffness calibration spring group 330 to convert the decrease in current into the loss value of spring compression.

[0075] S6. The loss value is sent as a micro-feed command to the servo drive component 210 to drive the motor for creep compensation.

[0076] In this embodiment, to address the force attenuation phenomenon caused by stress relaxation between lithium battery electrode layers, this method utilizes the current characteristics of a servo motor to achieve closed-loop pressure compensation.

[0077] In step S5, during the holding phase of servo motor position lock, the system continuously monitors the q-axis current of the motor, i.e. the torque component current. When the current value is detected to decrease relative to the target holding current, and the decrease exceeds the preset dead zone, it indicates that the load resistance has decreased, i.e., the battery has relaxed.

[0078] This preset dead zone is used to filter out non-substantial force fluctuations caused by servo motor current ripple and environmental micro-vibrations, preventing the system from frequently making unnecessary fine-tuning oscillations during the steady-state holding phase.

[0079] Based on the aforementioned electromechanical coupling model, the system performs the following derivation and calculation:

[0080] Calculate torque loss: ,in The amount of current decrease, The torque constant of the motor;

[0081] Calculate the axial force loss: ,in For transmission efficiency, For lead screw;

[0082] Calculate the loss value of spring compression: It should be noted that, due to Typically, the feed is at the micrometer level. Within this tiny stroke range, the hysteresis nonlinearity of the stiffness calibration spring assembly 330 is negligible. Therefore, a linear stiffness coefficient is approximated. Calculations are performed to simplify the control model.

[0083] In step S6, the system directly calculates the... The incremental position command is sent to the servo driver, which drives the motor to advance in microsteps, creeping forward and re-pressing the spring until the current returns to the target value. This process does not require the participation of an external pressure sensor; the constant restraint force can be maintained for a long period solely through feedback from the motor itself.

[0084] The steps in S4 include:

[0085] The current rise slope of the servo drive component 210 relative to the displacement is monitored in real time. When the current rise slope deviates from the calibration stiffness characteristic line of the stiffness calibration spring group 330, emergency stop protection is triggered.

[0086] In this embodiment, in order to prevent safety accidents caused by foreign objects inside the battery or bulging of the battery cells, the system introduces a slope monitoring mechanism based on a physical model.

[0087] In step S4, during compression, the system calculates the current rise slope in real time. Based on the proportional relationship between motor output torque and current, an equivalent stiffness characterization quantity is defined. Under normal operating conditions, since the stiffness of the stiffness calibration spring assembly 330 is constant, this slope... It should stabilize near the preset calibration stiffness characteristic line.

[0088] If metallic foreign objects or hard spots are present in the battery pack, the resistance will surge instantaneously, causing the real-time slope to be significantly greater than the calibrated stiffness characteristic line. If the battery leaks or its structure collapses, abnormal resistance will occur, causing the slope to deviate. Once the slope deviation exceeds the safety tolerance, the system immediately determines it as abnormal compression, triggering emergency stop protection and an alarm. This method utilizes the consistency of physical stiffness as a safety criterion, making it more predictive than simple force limit protection.

[0089] Example 2:

[0090] Please see Figures 1-2 A fully automatic restraint application and release device for a lithium battery restraint tray, comprising:

[0091] The main support frame 100 includes a base platform 110 and a gantry column 120;

[0092] The power transmission chain 200 includes a servo drive assembly 210 and a lead screw drive assembly 220. The servo drive assembly 210 is fixed to the base platform 110, and the lead screw drive assembly 220 is connected to the output shaft of the servo drive assembly 210.

[0093] The elastic buffer relay structure 300 is set on the guide rail of the base platform 110, including an active slider 310, a driven slider 320 and a stiffness calibration spring group 330. The active slider 310 is connected to the lead screw transmission assembly 220, the driven slider 320 is located in front of the active slider 310, and the stiffness calibration spring group 330 is set between the active slider 310 and the driven slider 320.

[0094] The adaptive constraint actuator 400 is connected to the front end of the driven slider 320.

[0095] In this embodiment, the overall layout of the device aims to combine high-rigidity support with high-precision transmission. The base platform 110 of the main support frame 100 is made of high-strength cast iron to absorb the vibration generated by the high-frequency acceleration and deceleration of the motor. The gantry-type column 120 forms a closed force flow loop to ensure that the frame does not undergo elastic deformation under heavy restraint forces. In the power transmission chain 200, the nut seat of the screw drive assembly 220 is directly rigidly connected to the active slider 310, converting rotational motion into linear motion. The elastic buffer relay structure 300, as the core component, converts rigid mechanical feed into flexible spring force output. The active slider 310 and the driven slider 320 are coaxially arranged on the guide rail, and power is transmitted between them through the stiffness calibration spring group 330, realizing the physical conversion from displacement control to force control.

[0096] The elastic buffer relay structure 300 also includes a limiting guide bolt. One end of the limiting guide bolt is fixed to the active slider 310. The rod of the limiting guide bolt passes through the stiffness calibration spring assembly 330 and enters the through hole of the driven slider 320. The head of the limiting guide bolt is located in the countersunk seat at the front end of the driven slider 320.

[0097] When the active slider 310 moves forward, it pushes the driven slider 320 through the stiffness calibration spring group 330. When the active slider 310 moves backward, it pulls the driven slider 320 to reset through the head of the limit guide bolt.

[0098] In this embodiment, the elastic buffer relay structure 300 adopts a clever "push-pull decoupling" design.

[0099] The limit guide bolt passes through the inside of the stiffness calibration spring assembly 330, which plays a role in preventing the spring from buckling laterally; the key lies in its connection logic: the tail of the bolt is fixed on the active slider 310, while the head is suspended in the countersunk seat at the front end of the driven slider 320.

[0100] It is important to note that the depth of the countersunk head is designed to exceed the maximum design compression stroke of the stiffness-calibrated spring assembly 330. This dimensional chain design ensures that when the active slider 310 compresses the spring forward, the limiting guide bolt moves forward accordingly, its head moving freely within the deep hole of the countersunk head without touching the bottom, thus guaranteeing that the thrust is entirely flexibly transmitted by the spring. Conversely, when the active slider 310 retracts to release its restraint, as the spring returns to its original length, the head of the limiting guide bolt eventually hooks onto the bottom step surface of the countersunk head, forcibly pulling the driven slider 320 backward. This structure achieves both flexible buffering during compression and forced reset during retraction, effectively preventing the driven slider 320 from becoming stuck due to guide rail resistance.

[0101] The adaptive restraint actuator 400 includes a floating connecting plate 410 and a restraint pressure head 420. The back of the floating connecting plate 410 is provided with an inwardly recessed joint bearing mounting seat, and the front end of the driven slider 320 is provided with a bearing bracket. The floating connecting plate 410 is connected to the joint bearing in the bearing bracket by a pin.

[0102] Among them, a pair of elastic anti-rotation pins are provided between the floating connecting plate 410 and the driven slider 320.

[0103] In this embodiment, to address potential parallelism errors on the battery tray surface, the adaptive restraint actuator 400 incorporates a biomimetic joint design. The floating connecting plate 410 is connected to the driven slider 320 via an embedded joint bearing, forming a ball joint structure that allows the pressure head to perform minute omnidirectional oscillations within space. This micro-motion capability enables the pressure head to automatically align itself and conform to the battery surface upon contact with the battery. Simultaneously, to prevent uncontrollable excessive rotation of the pressure head, a pair of elastic anti-rotation pins restrict its degrees of freedom, allowing it to oscillate only within a safe angle, achieving uniform force distribution and preventing excessive local pressure from damaging the battery cell.

[0104] The surface of the restraint head 420 is covered with insulating hard rubber, which has a hardness higher than 80 Shore D.

[0105] In this embodiment, the restraint indenter 420 directly contacts the charged battery terminals or casing, therefore insulation performance is crucial. The device uses a specially formulated insulating hard rubber with a hardness higher than 80 Shore D to cover the indenter surface. The selection of such a high-hardness material was based on precise calculations: under restraint forces of several tons, the elastic deformation produced by rubber of this hardness level is extremely small and negligible. This design aims to ensure that the elastic deformation of the entire system is mainly concentrated on the measurable element, the stiffness calibration spring assembly 330, avoiding soft deformation at the contact surface that is difficult to quantify, thereby ensuring the calculation accuracy of the force-displacement conversion model.

[0106] The servo drive assembly 210 includes an AC servo motor with an absolute encoder. The output shaft of the servo drive assembly 210 is connected to the lead screw drive assembly 220 via a plum blossom-shaped flexible coupling. The plum blossom-shaped flexible coupling has a plum blossom elastomer hardness of 98A.

[0107] In this embodiment, to ensure instantaneous response to control commands, the power transmission chain 200 is rigidly reinforced at the connection point. A quincunx flexible coupling is used between the servo motor output shaft and the lead screw, and the quincunx elastomer is made of 98A high-hardness polyurethane material. Compared to conventional flexible couplings, the 98A hardness elastomer has extremely high torsional rigidity, which can effectively suppress torsional backlash and elastic hysteresis when the motor frequently starts and stops. This means that every tiny rotation of the motor can be transmitted to the lead screw without loss. At the same time, tiny changes in the end load can be sensitively fed back to the motor's current signal through the rigid chain, providing a high signal-to-noise ratio physical basis for the aforementioned current monitoring algorithm.

[0108] 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 full-automatic restraining method for restraining and un-restraining a lithium battery restraining tray, characterized in that, Comprising: S1, setting a device comprising a main body support frame (100), a power transmission chain (200), an elastic buffer relay structure (300), and a self-adaptive restraint execution end (400); the power transmission chain (200) is composed of a servo drive assembly (210) and a lead screw transmission assembly (220), driving the driving slider (310) in the elastic buffer relay structure (300), driving the driven slider (320) and the self-adaptive restraint execution end (400) at the front end through the pre-pressed stiffness calibration spring group (330); S2, control the driving slider (310) to perform no-load full stroke scanning, record the motor current to generate mechanical friction resistance distribution curve and inertia compensation coefficient, and record the bidirectional load difference of the stiffness calibration spring group (330), and generate bidirectional hysteresis loss mapping table; S3, control the driving slider (310) to move forward and calculate the net load torque, after determining contact by continuous sampling exceeding the contact threshold, collect multiple groups of position and torque data in the shallow compression zone, and calculate the coordinate of the net load torque being zero as the virtual absolute zero point position through linear regression analysis; S4, according to the target restraint force and the stiffness coefficient of the stiffness calibration spring group (330), calculate the theoretical compression displacement, control the driving slider (310) to move from the virtual absolute zero point position by the theoretical compression displacement; The step of S4 includes: Determine whether the current motion state is pressurized loading or pressure unloading, index the bidirectional hysteresis loss mapping table according to the motion state, and find the hysteresis force difference value corresponding to the current target position; Divide the hysteresis force difference value by the stiffness coefficient of the stiffness calibration spring group (330) to convert it into displacement correction amount, and add the displacement correction amount to the theoretical compression displacement.

2. The full-automatic restraining method of the lithium battery restraining tray according to claim 1, characterized in that, The step after S4 includes: S5, continuously monitor the current fluctuation of the servo drive assembly (210) during the restraint maintaining stage, when it is detected that the current presents a downward trend, use the linear proportional relationship between the force and displacement of the stiffness calibration spring group (330) to convert the current drop to the loss value of spring compression amount; S6, send the loss value as a trace feed instruction to the servo drive assembly (210), and drive the motor to perform peristaltic compensation.

3. The full-automatic restraining method of the lithium battery restraining tray according to claim 1, characterized in that, The step of S4 includes: Real-time monitor the rising slope of the current of the servo drive assembly (210) relative to the displacement, when the rising slope of the current relative to the displacement deviates from the calibration stiffness characteristic line of the stiffness calibration spring group (330), trigger the emergency stop protection.

4. A full-automatic restraining device for restraining a lithium battery restraining tray, characterized in that, Comprising: The main body support frame (100) comprises a base platform (110) and a portal column (120); The power transmission chain (200) comprises a servo drive assembly (210) and a lead screw transmission assembly (220), the servo drive assembly (210) is fixed to the base platform (110), and the lead screw transmission assembly (220) is connected to the output shaft of the servo drive assembly (210); An elastic buffering relay structure (300) is arranged on the guide rail of the base platform (110), and comprises a driving slider (310), a driven slider (320) and a stiffness calibration spring set (330). The driving slider (310) is connected with the screw rod transmission assembly (220), the driven slider (320) is located in front of the driving slider (310), and the stiffness calibration spring set (330) is arranged between the driving slider (310) and the driven slider (320). An adaptive restraint execution end (400) is connected to the front end of the driven slider (320). A control system is electrically connected with the servo drive assembly (210) and is used for controlling the servo drive assembly (210) to execute the steps of the method in any one of claims 1 to 3.

5. The full-automatic restraining device for lithium battery restraining tray according to claim 4, characterized in that, The elastic buffering relay structure (300) further comprises a limiting guide bolt, one end of the limiting guide bolt is fixed to the driving slider (310), the rod part of the limiting guide bolt passes through the stiffness calibration spring set (330) and penetrates into the through hole of the driven slider (320), and the head part of the limiting guide bolt is located in the countersunk seat at the front end of the driven slider (320). When the driving slider (310) moves forward, the driven slider (320) is pushed by the stiffness calibration spring set (330), and when the driving slider (310) moves backward, the driven slider (320) is pulled back to the original position by the head part of the limiting guide bolt.

6. The full-automatic restraining device for lithium battery restraining tray according to claim 4, characterized in that, The adaptive restraint execution end (400) comprises a floating connecting plate (410) and a restraint pressure head (420), the back of the floating connecting plate (410) is provided with an inwardly recessed joint bearing mounting seat, the front end of the driven slider (320) is provided with a bearing support, and the floating connecting plate (410) is connected to the bearing support through a pin shaft and a joint bearing. A pair of elastic anti-rotation pins are arranged between the floating connecting plate (410) and the driven slider (320).

7. The full-automatic restraining device for lithium battery restraining tray according to claim 6, characterized in that, The surface of the restraint pressure head (420) is covered with insulating hard rubber, and the hardness of the insulating hard rubber is higher than 80 Shore D.

8. The full-automatic restraining device for lithium battery restraining tray according to claim 4, characterized in that, The servo drive assembly (210) comprises an AC servo motor with an absolute value encoder, the output shaft of the servo drive assembly (210) is connected with the screw rod transmission assembly (220) through a plum blossom elastic coupling, and the plum blossom elastic body of the plum blossom elastic coupling has a hardness of 98A.

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