Diaphragm technology restricts the development of lithium batteries Lithium - Ion Battery Equipment
It is understood that there are currently more than 200 power battery manufacturers in my country, which is the country with the largest number of power battery companies in the world. Statistics show that in 2017, among the top 10 companies in global power battery sales, Chinese companies accounted for 7 seats. According to Forbes News, China is expected to account for more than 70% of the global battery market by 2020.
Although my country has formed a relatively complete power battery industry chain, the scale is "big enough", but not "strong" enough. Some key core technologies are still controlled by others, and there is a risk of ZTE's "stuck neck".
Among them, lithium battery diaphragm technology is a pain point in my country's power battery industry. Among lithium-ion battery materials, the positive and negative electrode materials and electrolytes have basically been domestically produced, while the diaphragm started late, and the domestic enterprises' technology maturity is not high. Although the localization rate of lithium battery separators in my country 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, and high-end 3C batteries 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, the production capacity of pure electric vehicles and plug-in hybrid vehicles in my country will reach 2 million units per year. According to this estimate, the demand for high-quality automotive power battery separator materials in my country will reach hundreds of millions of square meters in the future.
As we all know, in the structure of lithium batteries, the separator is one of the key inner layer components, which 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, and the separator with excellent quality plays an important role in improving the overall performance of the battery.
It is reported that the separator is a high value-added material with the highest technical barriers among lithium battery materials, accounting for about 15% of the cost of lithium batteries. The technical difficulties lie in the engineering technology of pore making, matrix materials, and manufacturing equipment.
The current common problem of domestic diaphragms is that the consistency is not high, which is mainly manifested in irregular defects, substandard porosity, and uneven thickness, pore distribution and pore size distribution. The uniaxially stretched domestic PP separator is close to foreign products in terms of porosity and pore size distribution; the porosity of the biaxially stretched PE separator is usually lower than that of foreign products, and the pore size distribution is not ideal. These problems are all potential risks that the industry is "controlled by others". If not solved properly, it may curb the healthy development of my country'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 high levels. my country has a huge gap with the United States and Japan 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. my country's lithium-ion battery separators have made major breakthroughs in the dry process, but in the field of wet separators, domestic separator companies are limited by many factors such as process and technology, the product level is still low, and the production equipment relies heavily on imports.