Introduction to Lithium Battery Separator

In the structure of lithium batteries, the diaphragm is one of the key inner components. The performance of the diaphragm determines the interface structure and internal resistance of the battery, which directly affects the battery's capacity, cycle and safety performance. A diaphragm with excellent performance has an important purpose for improving the overall performance of the battery. The important purpose of the separator is to separate the positive and negative electrodes of the battery to prevent short-circuiting of the two poles in contact, and also has the function of allowing electrolyte ions to pass through. At present, among the four core materials of lithium batteries, the positive and negative electrode materials and electrolyte have been domestically produced, but the high-end lithium battery separator is still a technical shortcoming, and nearly 50% of the high-end separator still needs to be imported. The huge profits in the high-end diaphragm market have attracted many listed companies, and domestic substitution of imports is becoming a reality. It is expected to be put into operation in the second half of 2019, with an additional 1.5 billion square meters of wet-process diaphragm production and 150 million square meters of aluminum-plastic film production. Diaphragm, a small industry, was once the category with the highest technical barriers and the highest gross profit rate among the four major materials of lithium batteries, and it was also the category where domestic manufacturers made import substitution the latest. Now, while constantly eroding the share of foreign manufacturers, domestic diaphragm companies are also worrying about intensified price wars and declining gross profit margins, and import substitution is also stuck in an embarrassing situation. In order to improve the safety of lithium batteries and ensure the safe and stable operation of the battery, the diaphragm must meet the following conditions: 1. Chemical stability: Does not react with electrolyte and electrode materials 2. Wetting property: It is easy to infiltrate with electrolyte and does not stretch or shrink 3. Thermal stability: resistant to high temperatures, with high fuse isolation 4. Mechanical strength: good tensile strength to ensure that the strength and width of the automatic winding remain unchanged 5. Porosity: higher porosity to meet the needs of ion conductivity. Statement: 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 post: How to assemble a large-capacity lithium battery?