In the lithium battery manufacturing process, the bare cell hot-melt Mylar film process is a very important step in the battery preparation process. It plays a key role in ensuring the quality and safety of the battery. The bare cell core is coated with Mylar (Mylar film or Mylar film), which protects the bare cells and prevents internal short circuits. This process is crucial in the battery preparation process. After this layer of Mylar film is wrapped, it needs to be hot-melted on the top four sides, and the product and Mylar film Perform precise positioning. The Mylar film is tightly adhered to the bare battery core to effectively protect the bare battery core. At the same time, precise positioning can ensure that the Mylar film of each bare cell can be evenly heat-melted, thereby improving the overall quality and stability of the battery.
1. Mylar membrane and its functions
Mylar film is an insulating plastic film, usually composed of polyester film (PET), used to wrap the roll body and maintain insulation from the metal shell of lithium batteries. It has high temperature, high strength and high insulation properties and can be used for Bare cells provide effective protection. The role of the hot-melt Mylar film process for bare cells is to protect the bare cells and prevent internal short circuits. The bare cell is the core component of the battery, consisting of positive and negative electrodes and separators. During the battery preparation process, Mylar film is used to coat the bare battery core to externally protect the bare battery core to prevent the impact of external substances and the environment on the battery and to prevent the positive and negative electrodes inside the battery from being short-circuited.
The hot-melt Mylar film process is to wrap the Mylar film around the bare battery core, and use high-temperature hot-melt technology to tightly bond the Mylar film to the bare battery core. The precise positioning ensures that the Mylar film of each bare battery core can be evenly hot-melted. To improve the overall quality and stability of the battery.
2. Production process
1. Prepare the bare battery core: Prepare the bare battery core and clean and check the appearance and quality of the bare battery core.
2. Prepare Mylar film: Mylar film is usually cut according to the size of the bare battery core to ensure that it completely covers the bare battery core and provides sufficient protection.
3. Wrap the Mylar film around the bare cell: Precisely wrap the Mylar film around the bare cell, ensuring complete coverage and making sure there are no bubbles or wrinkles.
4. Hot-melt Mylar film: Use a hot-melt Myla device to hot-melt the Mylar film on the bare battery core, and hot-melt the top four sides of the battery core to ensure that the Mylar film and the bare battery core are tightly bonded.
5. Inspection and quality control: After completing hot melting, inspect the product to ensure that the hot melt Mylar film has no defects.
The above are the general steps of the hot-melt Mylar film process for bare cells. The specific steps may vary depending on the type of battery being prepared and the production process.
3. Precautions
1. Safety first: Ensure operators have adequate safety training and personal protective equipment to prevent accidents during the hot melt process.
2. Process parameters: Strictly control parameters such as hot melt temperature, time and pressure to ensure that the Mylar film can be firmly bonded to the surface of the bare cell.
3. Quality control: Establish a strict quality control system to inspect the size, appearance and bonding quality of bare cells and Mylar films to ensure stable product quality.
4. Operating procedures: Develop detailed operating procedures and standard operating procedures to ensure that each process can be carried out according to standards and reduce human operating errors.
5. Equipment maintenance: Perform regular maintenance on hot melt equipment to ensure the stability and reliability of the equipment.
4. Analysis of common problems and causes
During the hot-melt Mylar film process for bare cells, you may encounter some common problems, including:
1. The Mylar film is not firmly adhered: The reason is due to insufficient hot melt temperature, time or pressure, which will affect the safety and stability of the battery.
2. Bubbles or wrinkles appear in the Mylar film: The reason is that when wrapping the Mylar film, if the air is not properly removed or is not evenly wrapped around the bare battery core, bubbles or wrinkles will occur, affecting the appearance and performance of the battery.
3. Uneven hot melting of Mylar film: The reason is due to uneven hot melting equipment or inaccurate positioning of bare cells. Equipment or process parameters need to be adjusted.
4. Inconsistent sizes of bare cells: If the sizes of bare cells are inconsistent, it may cause improper Mylar film wrapping, affecting the quality and consistency of the battery.
5. Pay attention to safety during the hot melting process to avoid improper operation or equipment failure, which may cause injuries to workers.
5. Solutions
1. The Mylar film is not firmly bonded: Increase the hot-melt temperature, time or pressure to ensure that the Mylar film and the bare battery core can be fully bonded. Also check the status of the hot-melt equipment to ensure its normal operation.
2. Bubbles or wrinkles appear in the Mylar film: When wrapping the Mylar film, make sure to exclude air and wrap it evenly around the bare cell. Use appropriate process parameters and operating techniques to avoid these problems.
3. Avoid burns or scalds during the hot melting process: Operators need to be provided with adequate safety training to ensure that they understand the operating procedures of hot melting equipment and provide necessary personal protective equipment.
4. Uneven hot melting of Mylar film: It is necessary to adjust the parameters of the hot melting equipment to ensure uniform distribution of temperature, pressure and time. At the same time, the positioning of the bare cells must be adjusted to ensure that each bare cell can be evenly wrapped. .
5. Inconsistent size of bare cells: During the preparation process of bare cells, the size needs to be strictly controlled, and the consistency of bare cells needs to be improved by optimizing the preparation process and equipment.
6. Summary
Hot-melt Mylar film for bare cells is one of the key processes in battery manufacturing. Through strict control of process parameters, quality inspection and equipment maintenance, the quality and stability of battery products are ensured. At the same time, safety awareness and the formulation of operating procedures are also important factors to ensure the smooth progress of the process. By complying with the above precautions, the stability and consistency of the process can be effectively improved and the quality and safety of battery products can be ensured. In addition to the common problems and general solutions, it is also necessary to establish a complete quality control system and strictly monitor and inspect each process link. In order to ensure the stability and consistency of the hot-melt Mylar film process for bare cells, you can By adjusting process parameters, maintaining equipment, and training operators, we ensure the smooth progress of the hot-melt Mylar film process for bare cells to ensure the quality and safety of the battery.
