About the technical issues of high-end diaphragms for lithium ion batteries

　　At present, the trade war initiated by the United States to "Made in China 2025" continues to ferment, and the "ZTE Incident" has caused a strong shock in the industry. In recent days, the United States seems to be pointing its finger at the global communications equipment giant Huawei, once again touching the pain point of China's manufacturing industry that lacks core technology. In the raging trade war, the United States is pressing forward step by step and firing on multiple lines. China's power lithium battery industry must also beware of similar risks.

　　It is understood that there are currently more than 200 power battery manufacturers in China, which is the country with the most power battery companies in the world. According to data, among the top 10 companies in global power battery sales in 2017, Chinese companies accounted for 7 seats. According to Forbes News, it is estimated that China's share of the global battery market will exceed 70% by 2020.

　　Although China has formed a relatively complete power battery industry chain, the scale is large enough, but it is not strong enough. Some key core technologies are still restricted by others, and there is a risk of ZTE’s “stuck neck”.　　 Among them, the lithium battery separator technology is a pain point in China's power battery industry. Among the lithium-ion battery materials, the positive and negative electrode materials and electrolyte have basically achieved domestic production, but the diaphragm started late, and the technology maturity of domestic enterprises is not high. Although the localization rate of lithium battery separators in China has been increasing in recent years, it mainly occupies the low-end 3C battery separator market. The localization rate of high-end separators is still very low. The high-end 3C battery and power battery separators still rely heavily on imports. .　　 According to the "Energy-saving and New Energy Vehicle Industry Development Plan (2011-2020)" issued by the Ministry of Industry and Information Technology, by 2020, China's production capacity of pure electric vehicles and plug-in hybrid vehicles will reach 2 million units per year. Based on this estimate, in the future, the demand for high-quality automotive power battery separator materials in China will reach hundreds of millions of square meters each year.　　 As we all know, in the structure of lithium batteries, the separator is one of the key inner layer components. It not only prevents the positive and negative electrodes from contacting, but also ensures the passage of electrolyte ions. Therefore, the quality of the separator will directly affect the capacity, cycle and safety performance of the battery. A separator with excellent quality plays an important role in improving the overall performance of the battery.　　 It is reported that the diaphragm is currently a high value-added material with the highest technical barrier among lithium battery materials, accounting for about 15% of the cost of lithium batteries. The technical difficulty lies in the engineering technology, matrix materials, and manufacturing equipment for making holes.　　 The current common problem of domestic diaphragms is that the consistency is not high, which is mainly manifested in irregular defects, substandard porosity, uneven thickness, pore distribution and pore size distribution. Uniaxially stretched domestic PP diaphragms are relatively close to foreign products in terms of porosity and pore size distribution; bidirectionally stretched PE diaphragms are generally lower in porosity than foreign products, and the pore size distribution is not ideal. These problems are the potential risks of the industry being "subject to others". If they are not solved well, they may curb the healthy development of China's lithium battery industry.　　 It is understood that the PP diaphragm of Celgard Diaphragm Co., Ltd. and the PE diaphragm of Asahi respectively represent the highest level of products in the current diaphragm industry. Since Asahi acquired Celgard in 2016, the best diaphragm products have come from Asahi. Several other Japanese companies, such as UBE and Toray, also have a relatively high level. China has a huge gap with the United States, Japan and other countries in terms of PP diaphragm and PE diaphragm technology, and is in a passive position in the industrial chain.　　 At present, the preparation methods of lithium ion battery separators are mainly divided into wet method and dry method. China's lithium-ion battery separators have made major breakthroughs in dry process technology. However, in the field of wet process separators, domestic separator companies are limited by many factors such as process and technology, their product level is still low, and production equipment relies heavily on imports.　　 Like chips, high-end diaphragm technology has a very high threshold. It not only requires a huge investment, but also requires a strong R&D and production team, proficient process technology and high-level production line, and it will not be able to break through in a short time. However, the Sino-US trade war and the ZTE-Huawei incident have sounded the alarm for China's manufacturing industry. For the entire power battery industry, it is urgent to break through the high-end lithium battery diaphragm technology as soon as possible.　　 Fortunately, the existing domestic technology, Xingyuan Materials and other companies have made major breakthroughs in high-end diaphragm technology. I believe that in the near future, China's power lithium battery industry will be able to break the foreign technology monopoly and take the initiative in its own hands.　　 Changying is in hand, only then can Canglong be captured. Especially when China's manufacturing industry is facing the "headwind" of the international economy, only by mastering the core technology can you not be controlled by others, avoid the "ZTE" crisis, and become the true "market king"!