Recently, the Ministry of Technology and Equipment of China Petroleum and chemical industry has summed up the top ten technical needs of the oil and chemical industry through research. These things related to new materials, renewable energy, information and communication technology, such as the development of key technologies, currently in research and development or industrialization there are constraints, the need to break through, is the industry in the future a period of research and development focus.
This edition from today launched "The Oil and chemical industry ten urgently needed technology" series of reports, the development of these technologies and key issues with the reader to share. Ultra high Molecular weight polyethylene (UHMWPE) Lithium battery diaphragm is one of the most competitive diaphragm materials at present. In recent years, with the new energy vehicle battery life requirements of the continuous improvement, the UHMWPE lithium battery diaphragm demand also increased rapidly, ushered in the expansion of production tide.
At the same time its high gross profit also makes the diaphragm manufacturers of production technology development enthusiasm unabated, are trying to break through foreign technical barriers, master the independent preparation process.
Increased demand for superior performance The lithium-ion battery separator is the key inner component of lithium battery, which can affect the capacity of lithium battery, cycle performance and charge-discharge current density and other key performance, in the upstream part of the new energy automotive industry chain. In general, depending on the main function of the diaphragm, the diaphragm has a high performance requirement in terms of safety and accessibility.
UHMWPE Lithium-ion battery diaphragm has the advantages of maintaining dimensional stability at high temperatures, and strong resistance to puncture.
Yangtze Petrochemical Research Institute plastic Processing Center, Dr. Zo Shengwu, the current domestic membrane production process mainly dry and wet two major categories, dry method for polypropylene material, wet method for polyethylene material, UHMWPE battery isolation membrane material belongs to wet process. With the increase of battery life of new energy vehicles, the demand for ternary batteries is increased, and the three-cell batteries are almost used wet-process diaphragm, that is, UHMWPE battery isolation film. This diaphragm thickness is thinner, uniformity is better, aperture size easier to control, more favored by the market. ' In the next few years, the wet-separator will usher in a surge of expansion and demand in the market has risen sharply.
' said Zo Shengwu.
Technology breakthroughs face challenges In the development of new energy vehicles, the influx of capital, many domestic companies to obtain capital assistance, began to expand production scale, new capacity, the current domestic already has nearly 50 lithium battery diaphragm production enterprises, but also in many enterprises have new or build expansion device plans.
However, due to the rise of the domestic lithium membrane industry relatively late, most enterprises on the production process of the diaphragm is not comprehensive enough, resulting in many diaphragm production equipment is not able to normal production, and really on the scale of mass production enterprises are relatively small, the main reason is that the domestic has not fully mastered its production technology.
At present, domestic diaphragm manufacturers are trying to break through foreign technical barriers, the development of UHMWPE lithium battery diaphragm production technology, but more difficult, mainly reflected in the following aspects: One is that the traditional intellectual property of diaphragm preparation technology is dominated by a few countries such as USA, Korea, Germany and Japan, the development and production of our country is very late, independent intellectual property rights are scarce; second, the domestic enterprises to the production of diaphragm used upstream raw materials research is not in-depth, still do not realize the complete localization of diaphragm raw materials, The formulation research lacks the systematization, produces the diaphragm consistency, the uniformity and so on is poor, the pass rate is low, the mass production is difficult to realize; third, the diaphragm manufacturing process to equipment requirements, equipment operation and control accuracy is poor, directly affect the performance of the product, domestic equipment is generally difficult to meet the demand, but the import equipment prices are relatively high,
Therefore, the industrialization of the diaphragm received certain equipment restrictions.
Early stage of raw material localization Zo SHENGWU Introduction, China's lithium battery separator industry is in a high-speed development stage, it is estimated that only lithium-ion battery diaphragm with UHMWPE import volume reached 10,000 tons/year, and the trend of rapid growth.
However, limited by the technical level, the current domestic diaphragm enterprises used UHMWPE raw materials can only rely on imports. As early as 2010 years ago, Yangzi Petrochemical has been tracking cutting-edge technology, and has developed a new type of polyolefin raw material for lithium-ion batteries in parallel with the international petrochemical giants.
In 2013, the Yangzi Petrochemical Research Institute completed the small Test and pilot development of polyethylene diaphragm special material, and started the industrial development of UHMWPE special material for lithium ion battery separator. After technical research, Yangzi Petrochemical has solved the special Catalyst performance optimization, particle and shape control, product index consistency and other problems, in May 2017, Yangzi Petrochemical first realized the UHMWPE diaphragm special material YEV-4500 industrial trial production, filled the domestic blank,
Become the first successful development of lithium battery diaphragm material production enterprises, broke the product completely rely on the situation of imports, the first trial production of 100 tons of special materials. In April 2018, Yangzi Petrochemical also realized the industrial trial production of UHMWPE diaphragm special material yev-5201t, and tried to produce 150 tons.
At present, Yangzi Petrochemical Research Institute has negotiated with a domestic diaphragm manufacturers and reached a cooperative development intention, the relevant research and evaluation work is progressing smoothly.
Reporter also learned that lithium-ion battery diaphragm special resin research has been listed in one of the major projects of Sinopec-Power Battery material technology Development program.
Diaphragm Development heavy Responsibilities
Dr. Zo Shengwu admits that although the UHMWPE diaphragm special material has been achieved localization, but the development of lithium battery diaphragm is still a heavy task. Diaphragm raw material import cycle is long, qualified diaphragm needs to undergo the trial of lithium battery manufacturers, a evaluation to 3-6 months, at least through 3 evaluation, to be formally recognized.
At the same time, the diaphragm requirements of the continuous improvement of raw material impurity content, batch quality uniformity and even the requirements of the particle shape is very high, raw material development cycle long, the development of difficult, high threshold.