Lithium battery separator manufacturing knowledge

Analysis of the preparation methods of lithium battery separator manufacturing lithium battery separators are mainly melt stretching (MSCS) and thermally induced phase separation (TIPS), as shown in the following figure: The thermally induced phase separation (TIPS) method of preparing lithium battery separators is used Macromolecules and some high boiling point solvents form a homogeneous solution at high temperatures (generally higher than the polymer melting point Tm), lower temperatures and solid-liquid or liquid-liquid separation, which contains additives in the polymer phase, and rich In the polymer additive stage and stage, the stretching after the removal of low-molecular substances can form the interpenetration of the microporous membrane material. The thickness, strength, pore structure and number of the film can be adjusted by stretching and heat treatment before and after volatilization. Thermally induced phase separation can well control the pore size and porosity, but the disadvantage is that the solvent needs to be added and removed, which increases the cost and may cause pollution. The high polymer is mainly high-density polyethylene. The solvent can be phthalate, paraffin, alkane, ethanol, etc. The solvent can be used alone or mixed with a non-volatile organic solvent to dissolve the polymer at a higher temperature. Vinyl. In addition, in some cases, inorganic powder is added as a pore-forming accelerator and pore-controlling agent or as a crystal seed. The inorganic powder is evenly distributed in the sub-micron polymer phase. After adding the nucleating agent, due to the loose crystal structure, pores are easily formed during the stretching process, which will not cause pollution. The melt stretching (MSCS) method extrudes the molten polymer lithium battery from the mold and stretches it at a higher stretching ratio (stretching speed/extrusion speed) to form a wafer structure perpendicular to the extrusion direction. Arranged in parallel. After heat treatment, a highly oriented multilayer structure is obtained. After further stretching, the highly oriented crystalline polymer extends in the c-axis direction, and the crystal surface is peeled off to form a porous structure. After heat curing, a microporous membrane is prepared. The porous structure is related to the crystallinity and orientation of the polymer. Since the MSCS method does not include any phase separation process, the process is relatively simple and pollution-free, and it is a common method for preparing lithium battery membranes. However, it also has some disadvantages, such as pore size and porosity is difficult to control. 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 article: What kind of excellent performance of Ni-MH battery?