Why is Termination tape resistant to solvents and chemicals? ​

The resistance to solvents and chemicals of Termination tape is rooted in its unique material composition. Common termination tapes use insulating materials such as polypropylene, polyester or polyimide as the base material. Polypropylene is a high molecular polymer with a stable molecular structure, strong carbon-carbon bonds and carbon-hydrogen bonds, and is naturally resistant to common organic solvents and chemical reagents. When the electrolyte inside the lithium battery produces slight chemical erosion, the polypropylene base material can effectively block it, preventing the tape from being dissolved or reacting chemically, and maintaining its own structural integrity. Polyester materials, with their tight molecular arrangement and strong intermolecular forces, build a physical barrier against chemical erosion. The ester group in its structure interacts with other groups, making the polyester base material less likely to be penetrated and damaged by chemicals when facing the complex chemical environment inside the battery. As a high-performance engineering plastic, polyimide has excellent chemical stability. Its main molecular chain is composed of aromatic structure and imide group. This special structure gives polyimide extremely strong chemical corrosion resistance, and it can remain stable in high temperature and high concentration chemical environment. Even in the face of long-term erosion of electrolyte in lithium batteries, it can also maintain its insulating position. ​
In addition to the substrate, the acrylic glue for lithium-ion battery electrolyte coated by the termination tape is also the key to achieving solvent resistance and chemical corrosion resistance. Acrylic glue is made through a special polymerization process, and the molecular chains are cross-linked to form a three-dimensional network structure. This structure is tight and elastic. On the one hand, it can effectively prevent the invasion of solvent molecules. When the solvent in the lithium battery electrolyte tries to penetrate the tape, the three-dimensional network structure of the glue is like a solid filter, blocking the solvent molecules outside; on the other hand, the functional groups in the glue molecules interact with the groups on the surface of the substrate, which enhances the bonding force between the glue and the substrate, and further improves the overall chemical corrosion resistance of the tape. At the same time, the glue formula design is optimized for the chemical properties of lithium battery electrolytes, and monomers and additives with corrosion resistance are selected to enable it to not react chemically when in contact with the electrolyte, and always maintain stable bonding performance and physical form. ​
From the manufacturing process point of view, the production process of the termination tape is strictly controlled, which further enhances its solvent resistance and chemical corrosion resistance. In the raw material preparation stage, the quality requirements for the substrate and glue are extremely high. The substrate must be strictly screened to ensure that it has high purity, few impurities, and no defects that affect corrosion resistance; the glue is prepared according to a precise formula to ensure that the proportion of each component is accurate, so that the glue has the best chemical stability and bonding performance. In the coating process, high-precision coating equipment is used to evenly apply the glue on the surface of the substrate. The uniform coating not only ensures the appearance quality of the tape, but more importantly, it can form a continuous and complete protective layer to avoid the local corrosion resistance caused by uneven coating. The drying and curing process should not be ignored. By precisely controlling the temperature and time, the glue can be fully cross-linked and cured to form a stable chemical bond, improve the density and strength of the glue, and enhance its ability to resist chemical corrosion. Subsequent process links such as compounding and laminating, slitting and packaging also follow strict standards to prevent the introduction of impurities or damage to the tape during processing, which will affect its solvent resistance and chemical corrosion resistance. ​
With its solvent resistance and chemical corrosion resistance, termination tape plays a key role in lithium battery manufacturing. In the tabs and winding positions of cylindrical and square, small and medium-sized lithium-ion batteries and large power lithium-ion battery cells, termination tape plays an important role in terminating insulation fixation. During the charging and discharging process of lithium batteries, the tabs are the key nodes for current transmission, and they also face risks such as contact with electrolytes and puncture by other components. The termination tape is solvent-resistant and will not be dissolved or softened even if it is immersed in the electrolyte for a long time, and it always maintains a good physical form; its chemical corrosion resistance ensures that the insulation performance of the tape is not destroyed under the chemical erosion of the electrolyte, effectively preventing the short circuit between the pole ear and other components, and ensuring the safe and stable operation of the battery. For the winding position of the battery cell, the termination tape fits tightly to prevent external impurities from entering. At the same time, when the battery is impacted by external forces or changes in internal pressure, it protects the battery cell from damage and maintains the performance and life of the battery. ​
Throughout the life cycle of lithium batteries, the solvent resistance and chemical corrosion resistance of the termination tape continue to play a role. Starting from the battery production link, it provides reliable protection for the battery cell to ensure the smooth progress of the production process; during the use of the battery, whether the battery is in a high temperature or low temperature environment, or undergoes frequent charging and discharging, the termination tape can resist the erosion of the electrolyte, maintain stable performance, and ensure the normal operation of the battery; even after the battery is retired, the termination tape can still maintain its structural integrity, which is convenient for battery recycling and reduces environmental pollution and safety hazards caused by tape damage.