Web Tension Control Unit

The Web Tension Control Unit is a component-level subsystem used in lithium-ion battery electrode coating machines. Its primary function is to precisely regulate and maintain optimal tension in the moving electrode foil web throughout the coating, drying, and winding processes. By ensuring consistent tension, the unit contributes to uniform coating thickness, prevents wrinkles, and maintains dimensional stability of the electrode material. The unit operates by using tension sensors, such as load cells or dancer rollers, to measure actual web tension. This measured value is compared to a setpoint, and a closed-loop control system, typically a PID controller, adjusts braking or drive torque to correct any deviation. This control action compensates for speed changes, roll diameter variations, and other process disturbances, ensuring stable tension under varying conditions. The unit is designed for integration into coating machines and is available with a range of parameters that can be adjusted per process requirements. Key specifications include a tension range of 0.5–10 kN, tension accuracy of ±0.5% of setpoint under steady state, web speed range of 10–300 m/min (max speed depends on roll inertia), roll diameter range of 100–600 mm for unwinder/rewinder, control response time of ≤50 ms for 90% step response, supply voltage of 24 V DC ±10% (protected against reverse polarity), power consumption of ≤120 W (excluding actuators), operating temperature of 0–50 °C (non-condensing), ingress protection of IP54–IP65 per IEC 60529 for control cabinet and sensors, sensor type with analog output from load cells (0–10 V DC), communication interface options of Profibus DP, EtherCAT, or analog (1–2 channels), and weight of 15–60 kg depending on configuration. The unit is constructed with a stainless steel housing, precision bearings, ceramic-coated rollers, and electronic control components. These materials are selected for durability and performance in industrial environments. As a directory listing, the values provided are reference ranges; model-specific values and standards must be verified with the legal manufacturer or supplier before procurement or installation. The unit is not a standalone product but a component intended for integration into larger systems. Proper selection requires consideration of web material properties, line speed, roll inertia, and environmental conditions. Verification questions should address compatibility with existing control systems, sensor calibration, and compliance with relevant standards. Maintenance signals include deviations in tension accuracy, increased response time, or unusual wear on rollers. Failure boundaries include operation outside specified temperature or voltage ranges, which may lead to reduced performance or damage. The unit does not include actuators; these must be specified separately. For detailed technical data and installation guidelines, consult the manufacturer's documentation.

The unit measures actual web tension using load cells or dancer rollers. The measured signal is compared to a setpoint value in a closed-loop control system, typically a PID controller. The controller calculates the error and adjusts braking or drive torque to minimize deviation. This adjustment compensates for disturbances such as speed changes, roll diameter variations, and material property changes. The control loop operates continuously to maintain tension within the specified accuracy of ±0.5% under steady state. The response time is ≤50 ms for a 90% step change, enabling rapid correction. The system is designed to handle web speeds from 10 to 300 m/min and roll diameters from 100 to 600 mm. The control unit interfaces with sensors and actuators via analog or digital communication (Profibus DP, EtherCAT, or analog). Power is supplied at 24 V DC, and the unit consumes up to 120 W excluding actuators. The control cabinet and sensors are protected to IP54–IP65 per IEC 60529. The unit operates in temperatures from 0 to 50 °C and is protected against reverse polarity.