Motor Applications in Lithium Battery Electrode Coating Machines

1. Component Overview

The lithium battery electrode coating machine is a critical device in the electrode manufacturing process. It is mainly used to evenly coat slurry on metal foils (such as copper or aluminum), which directly affects battery consistency and performance. Its structure is highly precise and consists of the following components:

Coating Head System: Includes slot-die head, comma scraper, and fine-tuning mechanism. It is responsible for evenly applying slurry to the foil surface, requiring high-precision control of blade gaps and position.

Substrate Conveying System: Transports metal foil through synchronized rollers, traction rollers, and tension control systems. It must run smoothly and maintain accurate, consistent speed.

Drying System: Composed of multiple temperature-controlled zones, it uses infrared or hot air to dry the coating in stages, ensuring uniform heat distribution.

Unwinding/Rewinding Mechanism: Achieves high-precision tension control for raw material and finished products. With deviation correction, it prevents misalignment and wrinkling.

Control System: Includes motion controllers, tension controllers, and temperature regulators to centrally manage the entire coating line and provide feedback data.

2. Working Principle

During operation, the foil enters the coating area via the unwinding system. Under precise coordination of guide rollers and the tension system, the substrate is stably conveyed. Slurry is pumped to the coating head, and then applied evenly on the substrate by a slot-die or blade at an accurate thickness. The wet electrode sheet then passes through the multi-zone dryer, where the slurry is rapidly solidified into a film and finally wound up neatly through an edge-aligning system.

The entire process requires motors to provide stable line speed control, low-speed high-torque output, and synchronized coordination. For example, the speed matching between the drive roller and coating scraper determines the uniformity of the coating thickness; the unwinding motor must continuously adjust output torque to maintain constant tension; the rewinding motor uses closed-loop control to compensate for the load difference caused by changing roll diameter, ensuring consistent quality and edge alignment.

3. Motor Functions in the System

The coating machine demands motors with high precision, responsiveness, and low vibration. The key functions include:

Precision Line Speed Control: Servo motors drive the rollers, ensuring foil movement speed error is within ±0.1%, supporting coating speeds from 10 to 100 meters per minute.

Stable Tension Regulation: Servo or tension motors in the unwinding/rewinding units provide real-time compensation for material tension to prevent film thickness fluctuations.

Synchronized Operation: Multiple conveying and coating mechanisms require closed-loop synchronized motor control to ensure zero-error multi-axis linkage and avoid coating irregularities.

Heat and Corrosion Resistance: Motors often operate in high-temperature and solvent vapor environments, requiring heat-resistant windings, sealed construction, and anti-corrosion housing to ensure long-term stability.

Low Noise and Low Vibration: High-precision planetary reduction motors reduce mechanical fluctuation, effectively suppress edge fluttering of the electrode sheet and improve film quality.

4. Customized Motor Solutions

To meet the dual requirements of extreme stability and high-precision control in coating machines, we provide integrated drive and control solutions.

We recommend using high-response servo motors (e.g., GPG-SV130 series) paired with low-backlash precision reducers. These offer smooth output, precise positioning, and ±0.01° control resolution—perfect for coordinated control of speed and position in coating systems. This series also supports EtherCAT, CANopen, and other industrial protocols for easy system integration.

For the tension control module, we suggest the GPG-TM75 torque motor series, featuring built-in torque sensors and real-time PID tuning to automatically adapt to changing unwind diameters, ensuring consistent tension at high speeds.

For the fine adjustment system on the coating head, we offer the GPG-MI42 miniature stepper motor series, which enables micron-level position adjustments, improving edge uniformity and coating thickness consistency.

All motors support IP65+ protection, with stator windings using high-temperature enameled wire and corrosion-resistant packaging to ensure long-term operation in high-temp, high-humidity, and high-solvent environments.