Do you know what is the essential material of lithium battery separator?

In the structure of the lithium battery, the diaphragm is one of the key internal components. The performance of the diaphragm determines the battery's interface structure, internal resistance, etc., and directly affects the battery's capacity, cycle, and safety performance. According to the difference in physical and chemical properties, lithium battery separators can be divided into woven membranes, non-woven membranes (non-woven fabrics), microporous membranes, composite membranes, membrane paper, and laminated membranes. Although there are many types, the separator materials of commercial lithium batteries have mainly used polyethylene and polypropylene microporous membranes. Polyolefin materials have excellent mechanical properties, chemical stability and relatively inexpensive characteristics. Therefore, polyolefin microporous membranes such as polyethylene and polypropylene have been used as lithium battery separators in the early stage of lithium battery research and development. The market-oriented lithium battery separator material is mainly polyethylene (PE) and polypropylene (polypropylene, PP)-based polyolefin (Polyolefin) separators. Among them, PE products are mainly made by wet process, and PP products are important. Manufactured by dry process. As for the characteristics of the two lithium battery separator materials, PE and PP, in general: lithium battery separator.jpg1, PP is relatively more resistant to high temperatures, and PE is relatively resistant to low temperatures; 2. The density of PP is lower than that of PE; 3. PP melting point and closed cells The temperature is higher than PE; 4. PP products are more brittle than PE; 5. PE is more sensitive to environmental stress. Important lithium battery separator material products include single-layer PP, single-layer PE, PP+ceramic coating, PE+ceramic coating, double-layer PP/PE, double-layer PP/PP and triple-layer PP/PE/PP, among which the first two These products are mainly used in the field of 3C small batteries, and the latter products are mainly used in the field of power lithium batteries. Among the diaphragm material products for power lithium batteries, the double-layer PP/PP diaphragm material must be processed by Chinese companies and used in mainland China. This is important because no Chinese company can make PP and PE double-layer composite membranes at this stage. Technology and capabilities. The world's automotive power lithium battery separators are mainly composed of three-layer PP/PE/PP, double-layer PP/PE, PP+ceramic coating, PE+ceramic coating and other diaphragm material products. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous article: What are the characteristics of Tesla's BMS battery management system?