Li Xin: Ten years of grinding a sword, domestic lithium battery instead of imported goods

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

Li Xin, who has been a professional in welding, has been in the lithium battery industry for nearly 20 years. With the upgrading of the lithium battery casing material, Li Xin realized early that the original explosion-proof membrane will be eliminated sooner, but the lithium battery has a broad space for development.

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

In 2010, Li Xin took the Dongpu Film Company to settle in Baodi District and officially entered the diaphragm field. “Since the initial development of PE separators, we have benchmarked the industry leader – Asahi Kasei Corporation. Their products have an advanced HIPORE structure with an average pore size of 80-120 nm.”

The most advanced products have been identified, and the excellent performance of the products has been determined. Therefore, the structural design of the reversed product and the process and equipment that can smoothly realize this structure are the focus of research and development of Dongpu Membrane Company in recent years. In response to an important process in the production of base film, the stretching system, Dongpu Membrane Co., Ltd. pioneered the development and application of the simultaneous biaxial stretching process. Li Xin said that the synchronous double-drawing process can make the product into a more uniform hole and the consistency of the product microstructure is better, that is, the product performance is more stable.

At the same time as mastering the core technology, Dongpu Membrane also independently integrated a fully automatic production line. “Our production line has the advantages of high speed and wide width.” Li Xin said that the base film has a single line length of nearly 200 meters and the speed can be stabilized at 60 meters/minute.

According to reports, some imported base film production lines in China have a speed of about 25-30 m/min. “At present, the production capacity of our single production line can reach 78,000 square meters per year, which is twice that of them.” Li Xin said that the input-output ratio is large, the cost advantage is obvious, and it is more suitable for the popularity of power TV and electric vehicles. The low cost trend required.

"At present, Shenzhen Bickey Battery, Foster and other cylindrical lithium battery companies have applied our company's coated composite diaphragms in batches." Li Xin said that after 10 years of independent research and development, pilot and mass production, Dongpu Membrane Company has mastered Leading technology in the industry, enabling import substitution of high-end diaphragm materials

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