Learn more about battery insulation film: the key barrier to protect battery safety

At present, the new energy industry is booming, and the safety and performance of batteries, as the core energy storage components, have attracted much attention. The battery insulation film, this seemingly insignificant component, plays an irreplaceable key role in it.

Battery insulation film, in simple terms, is a film material with good insulation properties, mainly used in the battery, separate the parts of different potentials, to prevent the abnormal conduction of current. In the battery module, the cells are closely arranged, and once the insulation between the positive and negative electrodes is problematic, a short circuit may follow, causing serious consequences such as overheating, fire or even explosion of the battery. The battery insulation film is like a solid line of defense, effectively avoiding the occurrence of such dangerous situations and ensuring the stable operation of the battery.

There are a variety of common battery insulation film materials, of which polyethylene terephthalate (PET) is more commonly used. PET insulating film, commonly known as Mylar sheet, is milky white or light yellow, is a highly crystalline polymer with excellent physical and mechanical properties. In a wide temperature range, its performance is relatively stable, long-term use temperature can reach 120℃, excellent electrical insulation, can maintain good electrical properties at high temperature and high frequency, creep resistance, fatigue resistance, friction resistance and dimensional stability are excellent. PET insulating film price is close to the people, is widely used in electromechanical, electronic, information communication and other fields, in the battery module is often used as the insulation material between cells.

With the development of new energy vehicles, the performance requirements for battery insulation film are increasingly stringent. In terms of voltage strength, the common requirements are 3.7 kV AC or 4.2 kV DC, and some overseas projects even require up to 5 kV or 10 kV, and still maintain insulation in high temperature and high humidity environments; High temperature resistance is also crucial, the insulation film made of organic polymer materials usually does not exceed 400 ° C, but the temperature of the battery can reach 800-1200 ° C when the heat is out of control, which is a huge challenge for the insulation film; Flame retardant performance is also the focus of attention, after all, electric vehicle fire and explosion is the industry taboo; In addition, the vibration of vehicle operation requires that the insulating film has good bonding strength and shear resistance, and the long life cycle of the product also puts forward high requirements for its reliability, and it is also necessary to ensure good operability during the paste process to avoid bubbles or wrinkles affecting the production.

Although the battery insulation film is small, it plays a decisive role in the safety and performance of the battery. With the continuous progress of technology, it is believed that there will be insulation film materials with better performance, and promote the sustainable development of the new energy industry.