An ultra-precision air-floating roller applied to lithium battery production

Abstract

The application provides an ultra-precision air floating roller applied to lithium battery production and belonging to the technical field of lithium battery production equipment, which comprises a roller body assembly, an air source supply unit and an air pressure linkage control unit; an integrated precision air channel network optimized through fluid mechanics is arranged in the roller body base body of the roller body assembly, an air floating throttling layer with a micron-level air hole array is arranged on the roller surface, the air source supply unit supplies high-purity clean compressed air, the air is uniformly distributed through the air channel network, throttled and depressurized by the carbon surface treatment modification structure of the air floating throttling layer, and then sprayed out through the micron-level air hole array to form a stable supporting air film, the air pressure linkage control unit communicates with the air source supply unit, the thickness of the air film is controlled in the micron level, and the substrate tension is regulated and controlled through the air pressure-air film thickness-substrate tension linkage logic. The application realizes contactless transmission of the lithium battery substrate, solves the pain points such as material damage and tension out of control of the traditional contact transmission, and is suitable for the requirements of each process of lithium battery production.

Description

Technical Field

[0001] This invention belongs to the technical field of lithium battery production equipment, and more specifically, it relates to an ultra-precision air-floating roller used in lithium battery production. Background Technology

[0002] As a core energy storage component in the new energy industry, lithium batteries are undergoing rapid upgrades in manufacturing processes towards higher precision, higher yield, and higher efficiency. Substrate transfer is a key link in the core processes of lithium battery coating, cutting, winding, and stacking. The accuracy and stability of transfer directly determine the product quality, production efficiency, and yield of lithium batteries.

[0003] Currently, the mainstream method for lithium battery production is to use contact rollers for substrate transfer. This method has several technical drawbacks: First, the rollers are in direct physical contact with fragile substrates such as electrodes and separators, which can easily cause scratches, creases, and coating peeling, especially damaging micron-thin separators and wet electrodes, significantly reducing production line yield. Second, contact transfer is prone to tension fluctuations, making it difficult to achieve precise control, leading to substrate stretching, deformation, and misalignment, affecting the accuracy of subsequent cutting, stacking, and winding, and consequently causing quality problems such as high internal resistance and shortened cycle life in lithium batteries. Third, friction between the rollers and the substrate easily generates dust, and the roller material is prone to dust shedding, failing to meet the high cleanliness requirements of lithium battery production. Dust pollution can seriously affect the safety performance of lithium batteries. Fourth, contact friction causes rapid wear of the rollers, resulting in short equipment maintenance cycles, high downtime maintenance costs, and reduced effective production time of the production line.

[0004] To address these issues, a simplified air flotation roller structure has emerged in the industry. However, existing air flotation rollers generally suffer from unreasonable air channel design and uneven gas distribution, which can easily lead to air film imbalance and substrate misalignment. Furthermore, the outflow of air flotation is a scattering flow, which can easily cause impact disturbance to the substrate. At the same time, there is a lack of a precise air pressure-tension linkage control mechanism, resulting in low precision in air film thickness and substrate tension control. This makes it impossible to adapt to the differentiated transmission requirements of different processes in lithium batteries. In addition, the air source cleanliness control and the wear and temperature resistance of the air flotation layer are also difficult to meet the stringent requirements of high-end lithium battery manufacturing.

[0005] Therefore, developing an ultra-precision air-floating roller that can achieve contactless operation, high cleanliness, high precision, and multi-process adaptability has become an urgent technical problem to be solved in the high-end manufacturing field of lithium batteries. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides an ultra-precision air flotation roller for lithium battery production. It solves the problems of material damage, tension loss, insufficient precision, and substandard cleanliness associated with traditional contact-type substrate transfer in lithium battery production, as well as the technical problems of unreasonable air channel design, unstable air film, low tension control precision, and poor process adaptability of existing simple air flotation rollers.

[0007] An ultra-precision air-bearing roller for lithium battery production includes a roller assembly, an air supply unit, and an air pressure linkage control unit.

[0008] The roller assembly includes a roller base, the interior of which is provided with an integrated precision air channel network, and the roller surface of the roller base is provided with an air flotation throttling layer with a micron-level air hole array;

[0009] The air supply unit is used to deliver high-purity clean compressed air to the integrated precision air channel network. The integrated precision air channel network is designed with fluid dynamics optimization to evenly distribute the input compressed air to the air flotation throttling layer in the entire area of ​​the roller surface, ensuring the consistency of the pressure and flow rate of the compressed air in each area of ​​the roller surface.

[0010] The air flotation throttling layer is equipped with a carbon surface-treated modified structure, which is used to precisely throttle and reduce the pressure of the compressed air entering the blowing process, so that the compressed air is ejected in a stable and uniform state through the micron-level air hole array, forming a stable supporting air film between the roller substrate and the lithium battery substrate.

[0011] The air pressure linkage control unit is communicatively connected to the air source supply unit and is used to precisely adjust the output air pressure of the air source supply unit to achieve micron-level precise control of the supporting air film thickness. Through the linkage control logic of air pressure-air film thickness-substrate tension, the tension of the lithium battery substrate during transmission is finely controlled.

[0012] Preferably, the integrated precision air passage network includes a main air inlet chamber, multi-stage diversion branches, and a circumferential pressure equalization chamber. The multi-stage diversion branches are evenly distributed along the axial and circumferential directions of the roller body substrate to achieve uniform distribution of compressed air throughout the roller body cavity, thereby avoiding problems such as air film imbalance and substrate misalignment caused by uneven gas distribution.

[0013] Preferably, the air flotation throttling layer is made of porous graphite or porous ceramic material, and the micron-sized pore array is uniformly distributed across the surface of the air flotation throttling layer in a surface-source manner to form a continuous and uniform pressure output, thereby avoiding the impact and disturbance of the scattering flow on the lithium battery substrate.

[0014] Preferably, the carbon surface-treated modified structure of the air flotation throttling layer is a pore-modified throttling layer located on the air inlet side of the air flotation throttling layer. It is prepared by a carbon surface treatment process and is used to regulate the pore damping characteristics of compressed air, suppress air hammer effect and self-excited oscillation, reduce pressure fluctuation of the air film, and broaden the applicable transmission speed range of the air flotation roller.

[0015] Preferably, the pneumatic linkage control unit is pre-set with a mathematical model corresponding to the pneumatic pressure and the substrate tension. This model is used to adjust the output pneumatic pressure of the pneumatic supply unit in real time according to the transmission speed, material characteristics, and thickness parameters of the lithium battery substrate. This enables dynamic compensation and real-time control of the tension during substrate transmission, maintaining a stable transmission state without stretching or relaxation of the substrate.

[0016] Preferably, both the roller substrate and the air flotation throttling layer are made of stable materials that prevent dust shedding. The high-purity clean compressed air supplied by the air source supply unit is oil-free compressed air. Combined with the non-contact air film transmission structure, it is suitable for the high cleanliness requirements of lithium battery production and avoids substrate contact contamination and friction dust generation.

[0017] Preferably, the ultra-precision air flotation roller adopts a modular design, and the air pressure adjustment range of the air source supply unit, the air pore parameters of the air flotation throttling layer, and the size specifications of the roller body can all be adapted and adjusted according to the different process requirements of lithium battery production.

[0018] When the ultra-precision air-floating roller is applied to the lithium battery coating and drying process, the air pressure linkage control unit adjusts the output air pressure to a low pressure range, and forms a wide and uniform air film with the air-floating throttling layer to avoid damage to the wet electrode coating. At the same time, the air film suspension support enables the substrate to be heated evenly, improving the drying efficiency.

[0019] When the ultra-precision air-floating roller is applied to the lithium battery electrode cutting process, the air pressure linkage control unit activates a high-precision tension control mode to maintain the substrate in a wrinkle-free and offset-free transmission state, ensuring the micron-level precision of the cutting edge. When applied to the lithium battery separator transmission process, the uniform air film output by the air-floating throttling layer achieves complete isolation between the roller and the separator, avoiding scratches and creases on the separator, while reducing electrostatic adsorption through air film flow.

[0020] Preferably, the air flotation throttling layer has excellent wear resistance and corrosion resistance. Combined with the non-contact air flotation transmission method, it eliminates physical friction between the roller and the lithium battery substrate, significantly extends the equipment maintenance cycle, and reduces the time and cost of production line downtime maintenance.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention uses an air film as support to achieve contactless transmission between the substrate and the roller. Combined with the air flotation throttling layer source-type uniform outflow design, it avoids the impact of scattered flow on the substrate. At the same time, the ultra-precision polished surface of the air flotation throttling layer is burr-free, which can effectively prevent defects such as scratches, creases, and coating peeling from the electrode sheet, separator, and especially micron-level ultrathin substrates, and significantly improve the product yield of lithium battery production.

[0023] Achieving micron-level precision control of substrate tension: By constructing a linkage control logic of air pressure, air film thickness, and substrate tension, combined with a preset precise mathematical model and PID closed-loop control, the air pressure can be dynamically adjusted in real time according to the substrate material, thickness, and transmission speed. This enables micron-level control of air film thickness and precise regulation of substrate tension, keeping tension fluctuations within an extremely small range. This effectively solves the problems of substrate stretching, deformation, and misalignment caused by tension runaway in traditional transmission methods, improves the process accuracy of cutting, stacking, and winding, and provides core technical support for reducing the internal resistance of lithium batteries, improving cycle life, and optimizing safety performance.

[0024] Ensuring high-cleanliness transmission and meeting the stringent requirements of lithium battery production: The air supply unit provides high-purity, oil-free, clean compressed air through multi-stage precision filtration and deep drying. Both the roller body and the air flotation throttling layer are made of stable materials that prevent dust shedding. The non-contact transmission method avoids friction dust generation and contact contamination, meeting the ISO14644-1 Class 1 cleanliness requirements for lithium battery production throughout the entire process, eliminating the impact of dust contamination on lithium battery quality from the source.

[0025] Improve equipment stability, extend service life and reduce operation and maintenance costs: The integrated precision air channel network is designed with fluid dynamics optimization to achieve uniform gas distribution throughout the entire area, effectively avoiding problems such as air film imbalance and substrate deviation; The air flotation throttling layer is made of porous graphite or ceramic material, which has excellent wear resistance, temperature resistance and corrosion resistance. The non-contact transmission method eliminates physical friction between the roller and the substrate, greatly extending the roller maintenance cycle, reducing production line downtime and maintenance time and costs, and improving the overall production efficiency of the production line.

[0026] Modular design to adapt to the differentiated needs of the entire lithium battery production process: The air pressure adjustment range, air flotation throttling layer parameters, and roller size of this invention can all be flexibly adjusted according to process requirements. It also has multiple working mode presets such as coating and drying, electrode cutting, and separator transfer. It can be switched with one click to adapt to the transfer requirements of each core process in lithium battery production, solving the problem of poor process adaptability of existing air flotation rollers and improving the versatility and practicality of the equipment.

[0027] Suppressing air hammer effect and self-excited oscillation, and widening the applicable speed range: The carbon surface treatment modified structure of the air flotation throttling layer can regulate the pore damping characteristics, provide natural fluid damping for airflow, effectively suppress air hammer effect and self-excited oscillation, reduce air film pressure fluctuations, and enable the air flotation roller to achieve stable transmission in a wide speed range of 0-300m / min, meeting the development needs of high-speed production in lithium battery production lines.

[0028] Achieving uniform heating of the substrate and improving the efficiency of the coating and drying process: In the coating and drying process, the low-pressure, wide-width, uniform air film can completely suspend and lift the wet electrode, allowing both sides of the electrode to fully contact the hot air, achieving uniform heating. This not only avoids coating damage but also improves drying efficiency and uniformity, reduces coating defects such as streaks, orange peel, and drag marks, and further improves the quality of the finished electrode. Attached Figure Description

[0029] Figure 1 This is a diagram of the architecture of the present invention. Detailed Implementation

[0030] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] It should be noted that when an element is referred to as "fixed to," "set on," or "connected to" another element, it can be directly or indirectly on that other element. The terms "first" and "second" are used for descriptive purposes only. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] This embodiment discloses an ultra-precision air-floating roller for lithium battery production. It is mainly used for non-contact, high-precision transmission of lithium battery electrode sheets, ultra-thin separators and other substrates. It fully adapts to the production needs of the entire process of lithium battery coating, drying, cutting, winding and stacking, and solves the industry pain points of traditional contact transmission rollers, such as substrate scratches, tension loss, insufficient precision, substandard cleanliness and rapid equipment wear.

[0034] The ultra-precision air flotation roller comprises three core components: roller body assembly, air supply unit, and air pressure linkage control unit. These three components work together to achieve a closed-loop control of the entire process, including "uniform air supply, precise throttling, stable film formation, and dynamic tension regulation".

[0035] The roller assembly is the core actuator of the air flotation roller, including the roller body, an integrated precision air channel network, and an air flotation throttling layer. The three work together to achieve uniform distribution, precise control, and stable spraying of airflow.

[0036] In this embodiment, the roller body is made of aerospace-grade 6061-T6 / 7075 aluminum alloy, formed by precision machining and multi-stage stress-relief annealing to ensure the structural stability and dimensional accuracy of the roller body. The roller body roundness is ≤2μm, cylindricity ≤3μm, coaxiality ≤2μm, and surface roughness Ra≤0.4μm, meeting the dimensional tolerance requirements of ultra-precision transmission. Roller aluminum seats (end caps) are fixedly installed at both ends of the roller body. The air inlet end of the roller aluminum seat is equipped with a standard air inlet interface, which connects to the air supply unit via a high-precision rotary joint. The non-air inlet end of the roller aluminum seat is equipped with a sealed air plug, using a fluororubber sealing ring to achieve a complete seal, preventing gas leakage from the air passage and avoiding external dust and impurities from entering the air passage and contaminating the air source. The outer circumferential surface of the roller body is a precision mating surface used to bond and fix the air flotation throttling layer. The flatness of the mating surface is ≤2μm to ensure the sealing of the bond with the air flotation throttling layer and prevent airflow leakage from the mating surface.

[0037] The integrated precision air duct network is machined internally into the roller body. The overall structure is optimized using ANSYS Fluent fluid dynamics simulation. Based on Bernoulli's equation and the principle of uniform flow distribution, it employs a combination of gradient flow channels, equal-resistance branch flows, and a circumferential buffer pressure equalization chamber to achieve uniform distribution of compressed air throughout the roller body. This ensures that the gas pressure difference across different areas of the roller surface is ≤0.5% and the flow deviation is ≤1%. Specifically, the integrated precision air duct network comprises three parts: a main inlet chamber, multi-stage branch flows, and a circumferential pressure equalization chamber. The specific implementation details of each structure are as follows:

[0038] Main air inlet chamber: Located at the air inlet end of the roller body, directly connected to the air inlet interface. The chamber adopts a gradually expanding structure design with an air inlet diameter of 10-20mm. The cross-sectional area of ​​the chamber gradually increases along the airflow direction, and the expansion angle is controlled between 15° and 30° to avoid sudden expansion of the airflow, which would generate eddies and pressure loss, thus achieving initial stabilization and diffusion of the high-pressure input airflow.

[0039] Multi-stage flow branch system: This includes a primary axial flow branch system and a secondary circumferential flow branch system. The primary axial flow branch system is evenly distributed along the axial direction of the roller body, with 8-24 groups. All branches have the same flow channel length, cross-sectional dimensions, and inner wall roughness. The system adopts an equal resistance fluid dynamics design to ensure that the air intake flow rate at each point along the roller body axis is completely consistent. The secondary circumferential flow branch system is connected to the ends of the primary axial flow branch system and is evenly distributed along the circumference of the roller body. Each group of secondary circumferential flow branch systems corresponds to an independent circumferential pressure equalization chamber, realizing a secondary uniform flow distribution of airflow from the axial direction to the circumference.

[0040] Circumferential pressure equalization chambers: These chambers are arranged in a ring array along the circumference of the roller body, with their number matching the secondary circumferential flow branches. Each chamber is an arc-shaped buffer chamber, and its volume has been optimized through simulation design. This allows for secondary flow stabilization of the incoming airflow, eliminating airflow pulsation and ensuring that the static pressure difference at each point within the chamber is ≤0.5%. Ultimately, this ensures a completely uniform and stable airflow to the air flotation throttling layer on the roller surface. Additional implementation details: All inner walls of the air duct network are precision mirror-polished, with a surface roughness Ra≤0.2μm, significantly reducing frictional and local resistance and preventing turbulence and eddies within the flow channels. The entire air duct network is formed using a one-piece precision drilling process, without any splicing or welding, thus avoiding the sealing risks and abrupt flow channel changes associated with splicing and ensuring long-term stability of airflow transmission.

[0041] The air flotation throttling layer is bonded and fixed to the outer circumferential surface of the roller body substrate. It can be fixed to the roller body substrate using a heat-fit interference fit, high-temperature resistant inorganic adhesive, or mechanical fastening to ensure bonding strength and sealing performance. The thickness of the air flotation throttling layer is 3-10mm, and high-purity porous graphite or porous ceramic material can be selected according to the working conditions. The specific implementation parameters for both materials are as follows:

[0042] Porous graphite material: Selected isostatic high-purity graphite with a purity of ≥99.99%, porosity controlled between 15% and 40%, and an average pore size of 1-50μm. It has excellent self-lubricating properties, processing precision, and adaptability to throttling modification, and is suitable for diaphragm / electrode transmission processes with extremely high requirements for room temperature and cleanliness.

[0043] Porous ceramic material: 99% alumina ceramic or silicon carbide ceramic is selected, with porosity controlled between 20% and 45% and an average pore size of 2-30 μm. It possesses excellent high-temperature resistance, corrosion resistance, and wear resistance, making it suitable for high-temperature sections of coating ovens and special processes with corrosive atmospheres. The core structure of the air flotation throttling layer includes a micron-level pore array and a carbon surface-treated modified structure. Specific implementation details are as follows:

[0044] Micron-level pore array: It is uniformly distributed over the entire surface of the air flotation throttling layer in a surface-source manner. The single pore diameter is 5-20μm and the pore spacing is 10-50μm. The arrangement adopts an equilateral triangle array or a square array to ensure the uniformity of air output over the entire roller surface, forming a continuous and uniform surface-source airflow. This completely avoids the scattering flow and "needle-like wind" problems of traditional nozzle-type and slit-type air flotation rollers, and avoids impact disturbance to fragile substrates.

[0045] Carbon surface-treated modified structure: This is a pore-modified throttling layer located on the air inlet side of the air flotation throttling layer (the side that is in contact with the circumferential pressure equalization chamber). It is prepared by a vapor deposition carbon surface treatment process. Specifically, under a high-temperature vacuum environment, nanoscale carbon films are vapor-deposited on the air inlet side surface and pore inner wall of porous graphite / ceramic. By controlling the deposition temperature, time, and gas source concentration, the effective pore size and damping characteristics of the pores are precisely adjusted, so that the modified pores form uniform throttling damping throughout the entire domain. The core function of this structure is to precisely throttle and reduce the pressure of the high-pressure compressed air entering the air flotation throttling layer, transforming the high-pressure input airflow into a low-pressure, stable laminar outflow. At the same time, the modified pore structure has a natural fluid damping effect, which can effectively suppress the air hammer effect and self-excited oscillation of the airflow, control the pressure fluctuation of the air film to within 1%, significantly widen the applicable transmission speed range of the air flotation roller (0-300m / min), and reduce noise and stabilize the air film during operation. Additional implementation details: The outer surface of the air flotation throttling layer undergoes ultra-precision grinding and polishing, with a surface roughness Ra≤0.1μm and flatness≤2μm, ensuring the dimensional accuracy of the roller surface and preventing surface burrs from causing accidental scratches to the substrate; the air flotation throttling layer material itself does not shed dust, making it suitable for the high cleanliness requirements of lithium battery production.

[0046] The air supply unit provides high-purity, high-cleanliness, and pressure-stable adjustable compressed air to the air flotation roller, forming the basis for air film formation. Its output end is connected to a rotary joint at the air inlet of the roller via a stainless steel pipeline. In this embodiment, the air supply unit includes an oil-free air compressor, a three-stage precision filter assembly, an adsorption dryer, a high-precision electro-proportional pressure regulating valve assembly, a pressure / flow sensor, and stainless steel pipelines. Each component is sequentially and sealed along the airflow direction. Specific implementation details are as follows:

[0047] Oil-free air compressor: An oil-free screw air compressor is selected, which outputs clean, oil-free compressed air, eliminating the source of oil contamination of lithium battery substrates. The rated output pressure is 0.7-1.0MPa, which meets the air pressure input requirements of the air flotation roller.

[0048] The three-stage precision filtration system includes a primary filter (3μm filtration accuracy), a secondary filter (1μm filtration accuracy), and an ultra-precision filter (0.01μm filtration accuracy). It can remove dust, solid particles, oil mist, and aerosol impurities from compressed air step by step, and the cleanliness of the final output air meets the ISO14644-1 Class 1 standard, which is fully compatible with the high cleanliness requirements of lithium battery production.

[0049] Adsorption dryer: The double-tower adsorption dryer can control the pressure dew point of compressed air below -40℃, avoiding the condensation of water vapor in the air on the roller and substrate surface, and eliminating the problems of electrode coating getting damp and diaphragm absorbing water and deforming.

[0050] High-precision electro-proportional pressure regulating valve assembly: The core is a high-precision electro-proportional pressure regulating valve with a pressure regulating accuracy of ≤0.2%FS. It can receive analog / digital control signals from the pneumatic linkage control unit and adjust the output air pressure in real time and accurately. The continuous adjustment range of the output air pressure is 0.01MPa-0.5MPa, which fully covers the air pressure requirements of different substrates and different processes.

[0051] Pressure / flow sensor: Located at the output end of the pressure regulating valve assembly, it adopts a high-precision diffused silicon pressure sensor with a measurement accuracy of ≤0.1%FS. It can collect the actual air pressure and flow data in the pipeline in real time and feed it back to the air pressure linkage control unit to form a closed-loop air pressure control.

[0052] Piping and Accessories: All pipes, valves, and joints are made of 316L stainless steel, with the inner walls electropolished to ensure a burr-free and seamless surface, preventing dust shedding and impurity accumulation, and guaranteeing the cleanliness of the air source throughout the process. Additional Implementation Details: The air supply unit is connected to the roller substrate via a high-precision oil-free sealed rotary joint. This joint uses stainless steel and PTFE oil-free seals, adaptable to the high-speed rotation of the roller, maintaining zero leakage and no dust shedding at substrate transfer speeds of 0-300 m / min, meeting the requirements for long-term stable operation.

[0053] The pneumatic pressure linkage control unit is the core of the air-bearing roller control system. It is electrically connected to the air supply unit and production line sensors. The core achieves closed-loop control of air pressure, air film thickness, and substrate tension, while also providing multi-condition adaptation and abnormal alarm protection functions. In this embodiment, the pneumatic pressure linkage control unit includes a controller, a data acquisition module, a human-machine interface module, and a communication module. Specific implementation details are as follows:

[0054] Controller: It adopts a high-performance PLC controller or embedded motion controller, with built-in PID closed-loop control algorithm and preset mathematical model, which has high-speed data processing and real-time control capabilities, and control response time ≤10ms, meeting the dynamic adjustment requirements under high-speed transmission.

[0055] Data acquisition module: Electrically connected to the pressure sensor and flow sensor of the air supply unit, as well as the substrate speed encoder, tension sensor, and width sensor of the production line, it can collect operating parameters such as substrate transmission speed, actual tension value, actual air pressure and flow rate in real time, and transmit them to the controller for processing.

[0056] Human-machine interaction module: It adopts a touch screen display, which can display the operating parameters and alarm information of the air flotation roller in real time. It supports operators to manually set target tension and air pressure parameters, and switch preset working mode, making operation convenient.

[0057] Communication module: Supports industrial bus communication protocols such as Profinet, Modbus, and EtherCAT, enabling data interaction and linkage control with the main control system of the lithium battery production line, adapting to the automated production needs of the production line.

[0058] In this embodiment, the core air pressure-air film thickness-substrate tension linkage control logic is implemented as follows:

[0059] A pre-defined mathematical model corresponds to air pressure and substrate tension. This model was calibrated through fluid dynamics simulations and thousands of sets of experimental conditions. The input parameters of the model include: substrate type (electrode / diaphragm), substrate thickness (5μm-200μm), substrate transmission speed (0-300m / min), and target tension value. The output parameter of the model is the target output air pressure value of the air supply unit. The core calculation formula of the mathematical model is: P=k1·T+k2·v+k3·δ+C, where P is the target output air pressure (MPa), T is the target substrate tension (N / m), v is the substrate transmission speed (m / min), δ is the substrate thickness (μm), k1, k2, and k3 are calibration proportional coefficients, and C is a correction constant. Different substrate materials and types correspond to different coefficients and constants, which are pre-stored in the controller's storage module and can be directly called.

[0060] Real-time closed-loop dynamic adjustment: During the substrate transfer process, the data acquisition module collects the substrate transfer speed, actual tension value, and actual air pressure value of the air source in real time. The controller compares the collected real-time parameters with the preset target parameters and sends control signals to the electric proportional pressure regulating valve in real time through the PID closed-loop control algorithm to fine-tune the output air pressure, thereby accurately adjusting the air film thickness, realizing real-time compensation and dynamic control of substrate tension, and controlling tension fluctuation within ±0.1N.

[0061] Micron-level precise control of air film thickness: By precisely controlling the output air pressure of the air source, the air film thickness can be continuously adjusted within the range of 5μm-100μm, with a control accuracy of ≤±1μm; regardless of changes in substrate material, thickness, or transmission speed, it can be ensured that there is no physical contact between the substrate and the roller surface throughout the entire process, and smooth movement is achieved only through the buoyancy and support force of the air film.

[0062] Additional implementation details: The controller has multiple preset standard operating modes, including coating and drying mode, electrode cutting mode, separator transport mode, and winding and stacking mode. Each mode corresponds to a preset air pressure adjustment range, control parameters, and response speed. Operators can switch between modes with one click to quickly adapt to the needs of different lithium battery production processes. At the same time, the controller has comprehensive abnormal alarm and protection functions. When abnormal air pressure, excessive tension, insufficient air source pressure, or other faults are detected, it can immediately issue an audible and visual alarm signal and link the production line to perform a slow stop protection action to avoid batch scrapping of substrates.

[0063] The overall workflow of this invention:

[0064] The complete workflow of the ultra-precision air flotation roller in the lithium battery production process of this embodiment is as follows:

[0065] The air supply unit delivers high-purity clean compressed air that has been filtered, dried, and pressure stabilized to the integrated precision air channel network inside the roller body through a rotary joint.

[0066] Compressed air first enters the main intake chamber to complete the initial flow stabilization and pressure diffusion. Then, it passes through a multi-stage branch to complete the axial and circumferential equal resistance uniform flow splitting. It then enters the circumferential pressure equalization chamber to complete the secondary flow stabilization, ultimately ensuring that the airflow pressure and flow rate delivered to each region of the air flotation throttling layer are completely consistent.

[0067] A uniform airflow enters the air flotation throttling layer, first undergoes precise throttling and pressure reduction through the carbon surface treatment modification structure on the air inlet side to eliminate airflow pulsation, and then is ejected in a stable and uniform laminar flow state through the micron-level air hole array on the roller surface, forming a continuous and stable supporting air film between the roller surface and the lithium battery substrate, completely suspending and lifting the substrate to achieve contactless transmission.

[0068] During the substrate transfer process, the pneumatic linkage control unit collects parameters such as the substrate transfer speed, actual tension, and air source pressure in real time. Through a preset mathematical model and PID closed-loop control algorithm, it adjusts the output air pressure of the air source in real time to precisely control the air film thickness, thereby achieving fine dynamic control of the substrate tension and ensuring that the substrate remains in a stable state without stretching, loosening, deviation, or wrinkles during high-speed transfer.

[0069] The ultra-precision air flotation roller of the present invention adopts a modular design. The air pressure adjustment range of the air source supply unit, the material and pore parameters of the air flotation throttling layer, and the size and specifications of the roller body can all be adapted and adjusted according to the needs of different processes of lithium battery. The following are specific embodiments of typical processes.

[0070] Example 1: Application in the coating and drying process

[0071] This embodiment is applied in the oven of a lithium battery electrode coating machine. The substrate being transported is the coated wet electrode sheet. The coating on the wet electrode sheet is in an undried state and is fragile. Traditional contact rollers are prone to causing defects such as coating scratches, peeling, uneven thickness, and orange peel texture. Specific implementation method: Ultra-precision air-floating rollers are spaced along the length of the oven. The air-floating throttling layer is made of high-temperature resistant porous ceramic material, suitable for the high-temperature conditions of 80℃-150℃ inside the oven. The operator switches to the coating drying mode through the human-machine interface module. The air pressure linkage control unit adjusts the air source output pressure to a low pressure range of 0.02MPa-0.1MPa, which, together with the air-floating throttling layer, forms a wide and uniform air film with a thickness of 20μm-50μm. This ensures stable suspension support for the wet electrode sheet while avoiding coating damage caused by high-pressure airflow impact. Meanwhile, the uniform air film completely lifts the electrode, allowing both sides of the electrode to fully contact the hot air in the oven, achieving uniform heating of the substrate, greatly improving drying efficiency and uniformity, and avoiding problems such as electrode curling, uneven drying, and coating cracking. The surface-source uniform air outlet design results in low shear force and low eddy current in the air film, which can significantly reduce coating defects such as streaks, orange peel, and drag marks in the wet film, and improve the yield of finished electrode products.

[0072] Example 2: Application of electrode cutting process

[0073] This embodiment applies to a lithium battery electrode cutting machine. The substrate being transported is a dried electrode sheet. The cutting process has extremely high requirements for the flatness, positional accuracy, and tension stability of the electrode sheet during transport. Tension fluctuations and substrate misalignment can directly lead to defects such as out-of-tolerance cutting dimensions, edge burrs, and chipping, affecting subsequent battery assembly. Specific implementation method: An ultra-precision air-floating roller is installed at the feed end, discharge end, and tension control section of the cutting machine. Switching to cutting mode, the pneumatic linkage control unit activates a high-precision tension control mode, improving the tension control accuracy to within ±0.1N. Through real-time dynamic pneumatic compensation, the acceleration and deceleration tension fluctuations during high-speed cutting are effectively offset, ensuring that the electrode sheet is wrinkle-free, misaligned, and unstretched during transport. This provides a stable substrate state for high-precision cutting, ultimately achieving micron-level precision at the cutting edge, with a cutting dimensional tolerance ≤±5μm, significantly reducing the electrode sheet cutting defect rate.

[0074] Example 3: Application of ultra-thin diaphragm transport process

[0075] This embodiment is applied to lithium battery separator slitting machines and sheet-making machines. The transport substrate is an ultra-thin polypropylene / polyethylene separator with a thickness of 5μm-20μm. This substrate is extremely soft and easily scratched and creased. Furthermore, it is prone to electrostatic adsorption during transport. Traditional contact rollers can easily cause separator failure, affecting battery safety. Specific implementation method: Ultra-precision air-floating rollers are installed in each guide section of the separator transport. The separator transport mode is switched, and the output air pressure of the air supply unit is adjusted to 0.01MPa-0.08MPa. The air-floating throttling layer forms a uniform low-shear air film, completely suspending and supporting the separator, achieving complete physical isolation between the roller and the separator. This fundamentally avoids the generation of separator scratches, creases, and indentations. Simultaneously, the continuous airflow ejected from the roller surface forms a flowing air layer on the separator surface, effectively eliminating static electricity generated during separator transport and avoiding separator adhesion and wrinkling problems caused by electrostatic adsorption. This achieves damage-free, high-cleanliness, and stable transport of the ultra-thin separator.

[0076] Example 4: Application in winding / stacking processes

[0077] This embodiment is applied to lithium battery winding and stacking machines. The substrates being transported are electrodes and separators. In this process, the stacking accuracy and tension uniformity of the electrodes and separators directly determine the quality of the lithium battery core / stack, thus affecting the battery's internal resistance, cycle life, and safety performance. Specific implementation: An ultra-precision air-bearing roller is installed in the feeding tension control section of the winding / stacking machine. The pneumatic-tension linkage control unit achieves millisecond-level real-time dynamic compensation of tension through pneumatic-tension linkage control, effectively offsetting the acceleration and deceleration tension fluctuations during high-speed winding / stacking. This ensures that the electrodes and separators maintain a constant low tension state during transport, preventing stretching deformation. Simultaneously, uniform air film support prevents substrate misalignment, ensuring uniform interlayer pressure between the electrodes and separators, significantly improving the alignment accuracy of the core and stack (≤±10μm). This provides core process assurance for reducing lithium battery internal resistance, improving cycle life, and optimizing safety performance.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. For example, the material of the roller substrate can be replaced with stainless steel, titanium alloy, or other materials as needed; the pore parameters and pore array arrangement of the air flotation throttling layer can be adapted and adjusted according to the working conditions; the number of branch paths and chamber structure of the integrated precision air channel network can be optimized according to the roller size and width, all of which fall within the scope of protection of the present invention.

[0079] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. An ultra-precision air-bearing roller for lithium battery production, characterized in that, Includes roller assembly, air supply unit, and air pressure linkage control unit; The roller assembly includes a roller base, the interior of which is provided with an integrated precision air channel network, and the roller surface of the roller base is provided with an air flotation throttling layer with a micron-level air hole array; The air supply unit is used to deliver high-purity clean compressed air to the integrated precision air channel network. The integrated precision air channel network is designed with fluid dynamics optimization to evenly distribute the input compressed air to the air flotation throttling layer in the entire area of ​​the roller surface, ensuring the consistency of the pressure and flow rate of the compressed air in each area of ​​the roller surface. The air flotation throttling layer is equipped with a carbon surface-treated modified structure, which is used to precisely throttle and reduce the pressure of the compressed air entering the blowing process, so that the compressed air is ejected in a stable and uniform state through the micron-level air hole array, forming a stable supporting air film between the roller substrate and the lithium battery substrate. The air pressure linkage control unit is communicatively connected to the air source supply unit and is used to precisely adjust the output air pressure of the air source supply unit to achieve micron-level precise control of the supporting air film thickness. Through the linkage control logic of air pressure-air film thickness-substrate tension, the tension of the lithium battery substrate during transmission is finely controlled.

2. The ultra-precision air-bearing roller for lithium battery production according to claim 1, characterized in that, The integrated precision air passage network includes a main air inlet chamber, multi-stage diversion branches, and a circumferential pressure equalization chamber. The multi-stage diversion branches are evenly distributed along the axial and circumferential directions of the roller body substrate to achieve uniform distribution of compressed air throughout the roller body cavity, avoiding problems such as air film imbalance and substrate misalignment caused by uneven gas distribution.

3. The ultra-precision air-bearing roller for lithium battery production according to claim 1, characterized in that, The air flotation throttling layer is made of porous graphite or porous ceramic material. The micron-sized pore array is uniformly distributed across the surface of the air flotation throttling layer in a surface-source manner, forming a continuous and uniform pressure output, thus avoiding the impact and disturbance of the scattered flow on the lithium battery substrate.

4. The ultra-precision air-bearing roller for lithium battery production according to claim 1, characterized in that, The carbon surface-treated modified structure of the air flotation throttling layer is a pore-modified throttling layer located on the air inlet side of the air flotation throttling layer. It is prepared by a carbon surface treatment process and is used to regulate the pore damping characteristics of compressed air, suppress air hammer effect and self-excited oscillation, reduce pressure fluctuation of the air film, and broaden the applicable transmission speed range of the air flotation roller.

5. The ultra-precision air-bearing roller for lithium battery production according to claim 1, characterized in that, The pneumatic linkage control unit is pre-set with a mathematical model corresponding to the air pressure and the substrate tension. It is used to adjust the output air pressure of the air source supply unit in real time according to the transmission speed, material characteristics and thickness parameters of the lithium battery substrate, so as to realize dynamic compensation and real-time control of the tension during the transmission of the substrate and maintain a stable transmission state of the substrate without stretching or relaxation.

6. The ultra-precision air-bearing roller for lithium battery production according to claim 1, characterized in that, Both the roller substrate and the air flotation throttling layer are made of stable materials that prevent dust shedding. The high-purity clean compressed air supplied by the air source supply unit is oil-free compressed air. Combined with the non-contact air film transmission structure, it is suitable for the high cleanliness requirements of lithium battery production and avoids substrate contact contamination and friction dust generation.

7. The ultra-precision air-bearing roller for lithium battery production according to claim 1, characterized in that, The ultra-precision air flotation roller adopts a modular design. The air pressure adjustment range of the air source supply unit, the air pore parameters of the air flotation throttling layer, and the size specifications of the roller body can all be adapted and adjusted according to the different process requirements of lithium battery production.

8. The ultra-precision air-bearing roller for lithium battery production according to claim 7, characterized in that, When the ultra-precision air-floating roller is applied to the coating and drying process of lithium batteries, the air pressure linkage control unit adjusts the output air pressure to a low pressure range, which, together with the air-floating throttling layer, forms a wide and uniform air film to avoid damage to the wet electrode coating. At the same time, the air film suspension support enables the substrate to be heated evenly, thereby improving the drying efficiency.

9. The ultra-precision air-bearing roller for lithium battery production according to claim 7, characterized in that, When the ultra-precision air-floating roller is applied to the lithium battery electrode cutting process, the air pressure linkage control unit activates a high-precision tension control mode to maintain the substrate in a wrinkle-free and offset-free transmission state, ensuring the micron-level precision of the cutting edge. When applied to the lithium battery separator transmission process, the uniform air film output by the air-floating throttling layer achieves complete isolation between the roller and the separator, avoiding scratches and creases on the separator, while reducing electrostatic adsorption through air film flow.

10. The ultra-precision air-bearing roller for lithium battery production according to claim 1, characterized in that, The air flotation throttling layer has excellent wear resistance and corrosion resistance. Combined with the non-contact air flotation transmission method, it eliminates physical friction between the roller and the lithium battery substrate, significantly extending the equipment maintenance cycle and reducing the time and cost of production line downtime maintenance.

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