Self-developed domestic high-end diaphragms instead of imports have become a reality

　　Lithium batteries, which are mainly used for electric vehicles, have a huge market space. However, for many years, most of the high-end diaphragm materials for domestic lithium batteries have basically relied on imports or imported production lines. And Li Xin and his team have worked hard for 10 years to make it a reality to replace imported domestic high-end diaphragms with independent research and development.

　　Lithium batteries, which are mainly used for electric vehicles, have a huge market space. However, for many years, most of the high-end diaphragm materials for domestic lithium batteries have basically relied on imports or imported production lines. And Li Xin and his team have worked hard for 10 years to make it a reality to replace imported domestic high-end diaphragms with independent research and development.

　　Li Xin, who majored in welding, has been in the lithium battery industry for nearly 20 years. With the upgrading of lithium battery shell materials, Li Xin realized very early that the explosion-proof membrane they originally produced would be eliminated sooner or later, but lithium batteries have broad room for development.

　　So since 2004, he has been involved in the development and testing of wet diaphragms. "Lithium batteries are mainly composed of four parts, the positive electrode, the negative electrode, the separator and the electrolyte." Li Xin said that at that time, the technology of the positive and negative electrodes in the domestic market was relatively mature. However, there is no qualified separator manufacturer. "In lithium batteries, the most difficult thing to do is the separator, so we set the goal on the separator."

　　Benchmarking the most advanced products, confirming the excellent performance of the product, and then pushing back the structural design of the product, as well as the technology and equipment that can smoothly realize this structure, has been the research and development focus of Donggao Membrane Company in recent years. Aiming at an important process in the base film production link-the stretching system, Donggao Film Company took the lead in developing and applying the synchronous biaxial stretching process. Li Xin said that the simultaneous double-drawing process can make the product stretched hole more uniform, and the product microstructure consistency is better, that is to say, the product performance is more stable.

　　While mastering the core technology, Donggao Membrane Company also independently integrated a fully automatic production line. "Our production line has the advantages of high speed and wide width." Li Xin said, the single line length of the base film is nearly 200 meters, and the vehicle speed can be stabilized at 60 meters per minute.

　　According to the introduction, the speed of some imported base film production lines in China is about 25-30 m/min. "At present, our single production line can reach 70 to 80 million square meters of production capacity per year, which is equivalent to twice theirs." Li Xin said that the input-output ratio is large, the cost advantage is obvious, and it is more suitable for the popularization of power TVs and electric vehicles. The low-cost trend needed.

　　"At present, Shenzhen BAK Battery, Foster and other cylindrical lithium battery companies have applied our company's coated composite diaphragm in batches." Li Xin said that after 10 years of independent research and development, pilot trials, and accumulation of mass production, Donggao Membrane Co., Ltd. has The industry’s leading technology has realized the import substitution of high-end diaphragm materials.