What kind of influence does the separator have on the performance of lithium batteries?

The separator is one of the most critical internal components in the structure of a lithium battery. The important purpose of the separator is to separate the positive and negative plates to prevent battery short circuit while ensuring the normal passage of ions during charging and discharging to ensure the normal operation of the battery. Its performance directly affects the battery's capacity, rate, life and safety performance. 1. Thickness The uniformity of the thickness of the diaphragm is a particularly important quality index, which directly affects the appearance quality and even the internal performance of the diaphragm roll. It must be strictly controlled during the processing. In a highly automated diaphragm processing line, the diaphragm thickness is automatically detected and controlled by a highly accurate online non-contact thickness gauge and a fast feedback control system. The thickness uniformity of the diaphragm includes longitudinal thickness uniformity and lateral thickness uniformity. Among them, the lateral thickness uniformity is particularly important, and it is generally required to be controlled within 1 micron. 2. The pore size lithium battery diaphragm material itself has a microporous structure, and the distribution of micropores in the entire diaphragm material should be uniform. The electrode particles currently used are generally on the order of 10 microns, and the pore diameter is generally 0.03-0.12um. If the aperture is too small, resistance will be added. If the aperture is too large, it will easily make the positive and negative electrodes contact or be pierced by dendrites and short circuit. Generally speaking, the sub-micron pore size membrane is sufficient to prevent the direct passage of electrode particles. Of course, it is not ruled out that some electrode surfaces are not treated well, and some situations such as micro short circuits caused by more dust are not excluded. 3. Consistency Due to the different preparation processes, the consistency of the diaphragm may be quite different. Consistency includes self-characteristics such as closing temperature, as well as apparent consistency such as the consistency of the hole and thickness of the observation under the electron microscope. The higher the consistency of the diaphragm, the better for other aspects of performance. 4. The thermally stable diaphragm should be thermally stable within the temperature range (-20C~60C) where the lithium battery is used. Generally speaking, PE or PP materials currently used in diaphragms can meet the above requirements. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: How to correctly replace the UPS battery?