In the structure of lithium batteries, the diaphragm is an important internal component. The performance of the diaphragm determines the interface structure, internal resistance and other characteristics of the battery, which directly affects the capacity, cycling and safety performance of the battery, and an excellent diaphragm plays an important role in improving the overall performance of the battery. The main role of the diaphragm is to separate the positive and negative electrodes of the battery and prevent the electrolyte ions from passing through due to contact between the two poles. The diaphragm material is non-conductive and its physicochemical properties have a great impact on the performance of the battery. The types of battery packs differ and so do the diaphragms used. For lithium battery packs, since the electrolyte is an organic solvent system, organic solvent resistant diaphragm material is required, and high strength diaphragm polyolefin porous diaphragm is generally used.

PET film, also known as high temperature resistant polyester film, has excellent heat resistance, cold resistance, oil resistance and chemical resistance. According to its function, it can be divided into PET high-gloss film, chemical coated film, polyester anti-static film, polyester heat seal film, polyester heat shrink film, aluminized polyester film, etc.

Most of the traditional processing uses die-cutting, but for manufacturers with small quantities, multiple varieties and high processing accuracy requirements, the cost of opening the die is high and the accuracy is not up to standard. Therefore, the new technology laser cutting is increasingly adopted by various polyester film processing for its unique advantages of simple operation, automated operation and fine processing. For cutting of certain films, the use of red laser light will turn yellow. Therefore, beyond laser use of violet laser cold processing and low heat characteristics, the use of ultraviolet laser cutting polyester film just to make up for the shortcomings of red light processing.