Current status of research and development of separators for lithium batteries in my country

Current status of research and development of separators for lithium batteries in my country During an interview, a battery material expert told reporters that separators are one of the important components of lithium batteries. The important materials of separators are porous polymer membranes, including polyethylene and polypropylene. The separators used in lithium batteries have strict requirements on safety, permeability, porosity and thickness. In lithium batteries, charged ions move between the positive and negative electrodes to continuously form a current. The electrode and the separator are located between the positive and negative electrodes of the battery. This not only prevents direct contact between the positive and negative electrodes, but also ensures smooth passage of electrolyte ions. Zhou Zhen vividly explained that the battery electrolyte is like a river. The lithium ion diaphragm is built on the waist of the dam, such as the riverside trekking boat. A diaphragm hole is like a dam gate. Under normal circumstances, the ions are in the positive The negative poles continue to flow, and the cycle of charging and discharging ends. High-end diaphragms usually use ceramic materials. If the electrolyte temperature is too high, the material will expand, and the pores will close like a door, blocking the exchange of ions, thereby preventing the battery from bursting due to high temperature. Zhou Zhen said that the diaphragm is a material with the highest technical barrier that lithium battery funds have guessed. The technical difficulty lies in the engineering technology of the hole, the matrix material and the manufacturing equipment. The technical requirements are high, so the price is also high, accounting for more than 10% of the total cost of the battery. At present, the world's best lithium battery separator materials come from two Japanese companies, Asahi Chemical and Dongjiao Chemical, and 90% of the domestic lithium battery aluminum-plastic film market is exclusively owned by Japanese manufacturers such as Showa Denko. An engineer from Tianjin Lishen Company told reporters that compared with Japan, my country's high-end separation distance is obvious. The consistency of domestic diaphragm products is not high, and there are unqualified porosity, thickness, pore dispersion and pore dispersion unevenness. The quality of the diaphragm directly affects the battery capacity, charge-discharge cycle life, flame-retardant and anti-explosive safety functions. Industry insiders sigh with regret: a layer of diaphragm has two heavens, and it is a sunny day that strode through! Domestic diaphragms need to be broken. The current lithium battery diaphragm manufacturing process is mainly divided into wet and dry methods. The reporter learned in the interview that my country has entered the international first party in dry process, but in the field of wet diaphragm, although domestic companies have mastered the method, they still all compete with foreign giants. In addition, central processing equipment is also important to rely on import. Data show that in 2017, the domestic lithium battery market is planned to be about 113 billion yuan, and the power lithium battery is planned to be about 60 billion yuan. The 'Energy-saving and New Energy Car Industry Development Plan (2011-2020)' published by the Ministry of Industry and Information Technology also shows that by 2020, my country can only process 2 million pure electric vehicles and plug-in hybrid vehicles each year. According to the budget of the Battery Professional Association, the annual demand for high-quality automotive power lithium-ion battery separator materials will reach hundreds of millions of square meters. The development of lithium batteries cannot be controlled by others, and high-end materials such as diaphragms cannot be escaped! Wu Mengtao, general manager of Tianjin Bamo Co., Ltd. believes that such a huge market demand, completely dependent on foreign manufacturers, is not only unrealistic, but will also be a domestic driving force. The biggest concern for lithium batteries. High-end diaphragm technology has a high threshold, not only requires a large investment, but also a strong Ru0026D and processing team, skilled technology and high-level processing line. Regarding wet manufacturing, the extrusion and mixing process of resin materials and additives and the stretching process are two core difficulties. Zhou Zhen believes that domestic diaphragm companies want more, and it is necessary to use substrate surface treatment technology, such as tension glue technology, stamping product materials, equipment and process control, and three lessons in other fields. In addition, the upstream of the diaphragm industry chain includes Domestic coating machines, etc., the processing center equipment must also catch up, and complete a greater breakthrough in localization as soon as possible. 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: Eight precautions for lithium battery maintenance