In the production process of lithium-ion batteries, heat shrink film is a crucial step. Heat shrink film, like the "protective armor" of lithium-ion batteries （Such as lifepo4 battery、nmc battery、lto battery, etc）, looks thin, but it has many key missions to protect the safety, performance and stable operation of batteries.

The role of heat shrink film: Physical protection heat shrink film is usually made of high-strength polymer materials such as polyimide (PI) or polyester (PET), which has good wear resistance and impact resistance. In the production, transportation and assembly of batteries, it is inevitable to encounter various frictions and collisions. The heat shrink film can cover the surface of the battery shell like a solid shield, effectively preventing the shell from being scratched, dented, and other damages due to external forces.

For example, when transporting batteries from the production workshop to the assembly plant, the bumps of the vehicle and the collisions during transportation may cause damage to the batteries, and heat shrink film can greatly reduce this risk. In addition, heat shrink film also has excellent dust and water resistance, which can prevent dust, moisture and other impurities from invading the battery interior and delay their erosion of the battery shell metal, thereby reducing safety hazards and extending the battery life.

Electrical insulation

The outer shell of lithium-ion batteries is mostly made of conductive metals such as aluminum or stainless steel. When the batteries are grouped or assembled with other components, if the outer shell directly contacts external conductive parts, it is very likely to cause a short circuit, resulting in battery failure or even safety accidents. As a high-quality insulating material, heat shrink film can form a reliable insulation barrier between the battery shell and external conductive parts to prevent accidental conduction of current and ensure the electrical safety of the battery. Moreover, high-quality heat shrink films need to pass strict voltage resistance tests, which generally require a voltage resistance value of ≥3000V DC, so that the heat shrink film can also play a long-term and stable insulation role in high-voltage battery packs to ensure the reliability of the battery system. For example, in the battery module of an electric vehicle, many batteries are closely arranged, and the insulation performance of the heat shrink film is particularly important. It can effectively prevent short circuits between batteries and ensure the normal operation of the entire battery system.

Thermal management assistance

During the battery charging and discharging process, a large amount of heat will be generated. If the heat cannot be dissipated in a timely and effective manner, the performance and life of the battery will be seriously affected. Some heat shrink films are designed with thermal conductive coatings to help distribute the heat on the battery surface more evenly. Combined with heat dissipation devices such as liquid cooling plates, the heat dissipation efficiency can be significantly improved, so that the battery always remains within a suitable operating temperature range. In addition, some heat shrink films also add flame retardants such as nitrogen or phosphorus. In the early stage of thermal runaway of the battery, these flame retardants can play a role in delaying the spread of the fire and buying precious time for personnel evacuation and emergency measures, thereby greatly improving the safety of the battery. For example, in some energy storage power stations, a large number of batteries are concentrated together. Once thermal runaway occurs, the consequences are disastrous. Heat shrink films with flame retardant properties can curb the deterioration of accidents to a certain extent.

Identification and traceability management

The heat shrink film can also be used as an identification and traceability carrier for batteries. By printing QR codes, batch numbers, production dates and other information on the heat shrink film, the battery can be easily tracked and managed, and the product's full life cycle traceability can be achieved. This is of great significance for ensuring product quality, solving after-sales problems, and recalling defective products. In addition, the heat shrink film can also be designed with different colors and textures to make the appearance of the battery more beautiful and unique, meeting consumers' personalized needs for product appearance.