Lithium battery diaphragm technology difficulties and processing technology analysis

What are the difficulties of lithium battery diaphragm technology? Many domestic companies are trying to break through foreign technical barriers and develop lithium battery separators, but it is difficult. The difficulty is mainly reflected in the following three aspects: First, the patents related to the traditional preparation of diaphragm technology are basically monopolized by a few companies in the United States and Japan, and China lacks independent intellectual property rights in processing technology; second, the key technology of domestic companies in processing lithium battery diaphragms In particular, the industrialization technology is relatively lacking. Many companies can often produce better samples in small-scale tests, but the consistency of products is poor during large-scale processing. Third, China’s research on new processes and new methods is very different. International synchronization, but new processes often have higher requirements for equipment and process control. China’s precision production equipment is relatively weak, which restricts industrialization. Despite the difficulty, domestic lithium battery separators have already started. Now some domestic companies have made some technological breakthroughs in localization, such as Shenzhen Xingyuan Material Technology Co., Ltd., Foshan Jinhui High-tech Optoelectronic Materials Co., Ltd., Henan Xinxiang Green New Energy Materials Co., Ltd., etc. All have processed lithium battery separators with independent intellectual property rights, but most of them are currently supplied to the middle and low-end markets, and the membrane technology needs to be further matured. The high-tech barriers of diaphragms are relatively high in the entire power lithium battery raw materials. The core technology is monopolized by companies in some countries such as Japan and the United States. As a result, the quality of diaphragms processed by my country's diaphragm processing companies is still far from the international level. Lithium battery separator processing technology At present, there are two important processing methods for lithium battery separators: dry method (melt stretching method) and wet method (thermally induced phase separation method). Dry-process film is an important process for PP film. The process has experienced decades of development and is relatively mature. It is specifically divided into unidirectional stretching and bidirectional stretching. The current commonly used method in my country is unidirectional stretching. Wet method is a technology that has only emerged in recent years, and it is important to process PE film. The dry process is mainly to melt the polyolefin resin, extrude it into a crystalline polymer film, obtain a high crystallinity structure after crystallization, and then stretch it at a high temperature to peel off the crystalline structure to form a porous film. The method has mature equipment, relatively simple process, and pollution-free processing. The wet process is mainly to mix liquid hydrocarbons or some high-boiling small molecular substances with polyolefin resins and melt them, and then prepare interpenetrating microporous membranes through processes such as extrusion, casting, biaxial stretching, and extraction. It can be seen that the lithium battery wet-process film is related to the dry-process film, and its process flow is more complicated, so it is more suitable for high-power, high-capacity batteries. The increase in subsidy thresholds, consumer demand for high-range electric vehicles and safety performance requirements have directly increased the requirements for battery capacity and power, thereby bringing more opportunities to the wet film market. Lithium battery diaphragm processing technology is complicated and technical barriers are high. Diaphragm processing technology includes raw material formula and rapid formula adjustment, micropore preparation technology, independent design of complete equipment and many other processes. Among them, the micropore preparation technology is the core of the lithium battery diaphragm preparation process. According to the difference in the micropore formation mechanism, the diaphragm process can be divided into two types: dry method and wet method. Disclaimer: The articles published on this website are all from the Internet. If there is any infringement, please contact to delete it. 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: How does the battery work? What are the precautions for battery use