Introduction

Cylindrical battery winding machines are pivotal equipment in the manufacturing of cylindrical lithium-ion battery cells. They serve the primary function of winding positive and negative electrode sheets along with separators in a specific sequence and according to process requirements, forming a cylindrical cell structure. This article will elaborate on the role and operating principle of cylindrical battery winding machines, discussing their components, operational steps, and advancements in the field.

The Role of Cylindrical Battery Winding Machines

Cylindrical battery winding machines are essential in the production of cylindrical lithium-ion battery cells. The main raw materials for these machines include battery cathodes, anodes, separators, and electrolytes. These materials are wound into electrode sheets of a certain thickness and further processed through a series of automated processes to form cylindrical electrode cores. The role of these machines can be summarized as follows:

Material Integration: By winding positive and negative electrode materials, separators, and electrolytes together, cylindrical battery winding machines integrate these components into a cohesive structure.

Precision Manufacturing: The machines ensure precise control over factors such as tension, width, and thickness during the winding process, leading to high-quality battery cells.

Efficiency Enhancement: Automated winding machines significantly increase production efficiency, reducing manual intervention and minimizing errors.

Product Consistency: They ensure uniformity in battery cell production, which is crucial for the performance and reliability of the final battery products.

Operating Principle of Cylindrical Battery Winding Machines

The operating principle of cylindrical battery winding machines involves several critical steps, including material cutting, arrangement, winding, and trimming. Here is a detailed breakdown:

Material Cutting:

Positive and Negative Materials: The positive and negative electrode materials are cut to specified lengths, widths, and quantities.

Separators: Separators are also cut to the required size to fit between the positive and negative electrode materials.

Arrangement:

The cut materials are arranged on the working table of the winding machine according to the design requirements of the battery cell. This involves layering the positive and negative electrode materials with separators in between, ensuring they are in the correct sequence and position.

Winding:

The arranged materials are placed on the winding shaft of the machine.

An automated control system regulates the tension, width, and thickness of the winding process.

The winding shaft rotates, drawing the materials through and winding them into a cylindrical shape.

Trimming:

After winding, the electrode sheet ends are trimmed to ensure they meet the design specifications of the battery cell in terms of length and width.

Components of Cylindrical Battery Winding Machines

Cylindrical battery winding machines consist of several key components that work together to achieve the winding process:

Unwinding Mechanism:

This component handles the fixed, automatic unwinding of electrode and separator rolls.

It uses mechanical or pneumatic expansion methods, assisted by positioning blocks and edge detection mechanisms for quick positioning.

Tension Control System:

Composed of tension sensors, actuators, and display/storage modules.

The tension actuators include linear motors, low-friction cylinders, or servo motors.

The tension control system ensures precise tension control during the winding process, preventing deformation of the bare cell due to winding tension issues.

Winding Mechanism:

Equipped with two or more winding needles and a single-side needle extraction structure.

It introduces electrode sheets into the winding section via a clamp roller drive mechanism, winding them together with separators according to process requirements.

Automatic Correction Module:

Consists of multiple correction stages, using methods such as hanging shaft movement, guide roller oscillation, and clamp roller drive for correction.

Real-time detection, control, and display of material edge position during tape travel ensure real-time correction of material edges.

Electrode Sheet Feeding Module:

Composed of positive and negative clamp roller drive mechanisms and feeding mechanisms.

Ensures effective, low-noise, pollution-free feeding of electrode sheets before winding.

Electrode Cutting Module:

Composed of positive and negative electrode pressing and cutting mechanisms.

Automatically detects the tail mark hole of the electrode sheet, counts to the set number of electrode tabs, or recognizes the electrode tab spacing, and cuts the electrode sheet after traveling a set length.

Defective Electrode and Separator Removal Module:

Composed of servo motors, couplings, and linear guide mechanisms.

Programmed to remove defective positive and negative electrodes independently, either with or without separators.

Separator Cutting Module:

Consists of a thermal cutting blade mechanism and protective mechanisms.

Cuts separators to the required length and immediately adsorbs them to prevent curling due to static electricity.

Termination Tape Application Module:

Composed of automatic adhesive application, tape mark hole sensors, and tape application rollers.

Automatically applies tape to the corners or ends of the bare cell.

Pre-Pressing and Unloading Module:

Automatically unloads the bare cell from the winding needle, pre-presses it during transport, scans the QR code on the cell surface, and transfers it to the unloading machine via a conveyor belt.

Types of Cylindrical Battery Winding Machines

There are two main types of cylindrical battery winding machines: pneumatic winding machines and fully automatic winding machines.

Pneumatic Winding Machines:

Traditional winding equipment controlled by cylinders.

Relatively slow winding speed and requires manual adjustment.

Fully Automatic Winding Machines:

Fully automated equipment with faster winding speeds and higher precision.

Based on computer control systems, it automates winding, cutting, and electrode replacement processes, improving production efficiency and line stability.

Advancements and Future Directions

With the increasing market demand and rapid development of new energy fields such as electric vehicles and photovoltaic energy storage, cylindrical battery winding machines have a broad development prospect as one of the core equipment in the entire battery manufacturing process. Future advancements in this field include:

High Speed and High Precision:

Enhancements in winding efficiency and precision through technological breakthroughs in continuous and uniform separator movement.

High Yield Rates:

Improvements in defect detection and removal systems to increase product yield rates.

Stability and Reliability:

Enhancements in machine stability to increase mean time between failures (MTBF).

Laser Cutting and Winding Integration:

Combining laser cutting and winding processes into a single integrated piece of equipment.

Conclusion

Cylindrical battery winding machines play a crucial role in the production of cylindrical lithium-ion battery cells. By integrating positive and negative electrode materials, separators, and electrolytes into a cylindrical electrode core structure, these machines ensure high-quality, consistent, and efficient battery cell production. With advancements in technology, these machines are becoming increasingly automated, precise, and reliable, paving the way for further innovations in the battery manufacturing industry. The future of cylindrical battery winding machines is promising, with ongoing developments aimed at improving speed, precision, yield rates, and stability.