How to seek breakthroughs in lithium battery materials under the pressure of the demand for new energy vehicles?

In the next five years, the lithium ion battery market for new energy vehicles will see an average annual growth rate of about 50%. The technological progress of lithium ion battery mainly comes from the progress in the innovation, research and application of key battery materials. Through the development of new materials, further improve the battery performance, improve the quality, reduce the cost and improve the safety.

Recently, on the BBS meeting of lithium battery industry and technology development, many experts discussed the new development demand of lithium battery for new energy vehicles, how to adapt lithium battery diaphragm, electrode material, electrolyte and other new development trend under the new situation, and how to seize the investment opportunity in the power lithium battery material industry. Experts and scholars from new energy automobile enterprises, scientific research institutes and industry associations brought audio-visual feast to the participants.

Annual increase of 50% in power battery market

Chen keyu, deputy head of the energy storage department of chengdu yajun new energy vehicle technology co., LTD., pointed out that new energy vehicle power batteries are faced with problems such as high battery price, long charging time, short range, poor environmental versatility and short service life. Therefore, new energy vehicles put forward a new development demand for lithium battery: one is to improve the consistency of high temperature, low temperature, charging and discharging.

The second is to achieve high charging rate through battery design and material improvement. The third is to improve the energy density, mainly by optimizing the electrode structure based on the existing high-capacity material system and increasing the load of active material. Application of new material system to improve the working voltage of battery; Optimize the new material system, using the new battery structure to achieve. Fourth, improve security, especially under extreme conditions. Fifth, reduce costs. Sixth, pay attention to the secondary recycling of batteries.

Liu yanlong, secretary-general of the China chemical and physical power industry association, said the lithium ion battery market for new energy vehicles will see an average annual growth rate of about 50 percent in the next five years. The technological progress of lithium ion battery mainly comes from the progress in the innovation, research and application of key battery materials. Through the development of new materials, further improve the battery performance, improve the quality, reduce the cost and improve the safety.

Liu yanlong pointed out that lithium ion battery electrolyte and diaphragm to improve the performance and safety of the battery is becoming more and more important, electrolyte additives and diaphragm coating with lithium ion battery to enhance voltage (enhance energy density), maintain life and ensure the safety of important measures. In the field of battery electrolyte, it is necessary to focus on the functional electrolyte.

In particular, new electrolyte systems (including solvents, solutes and additives), functional electrolytes (including additives) suitable for high nickel NCM power batteries, electrolytes (including additives) suitable for energy storage batteries, low-temperature electrolytes, high-temperature electrolytes (150 c) and flame retardant electrolytes are highlighted.

Coated (or composite) diaphragm is now the focus of diaphragm application development, diaphragm surface coating layer, one is to improve the thermal stability of the diaphragm; Second, it can improve the infiltration of the membrane to the electrolyte, which is conducive to reducing the internal resistance of the battery and improving the discharge power. Third, the coating can prevent or reduce the membrane oxidation, which is conducive to cooperate with the operation of high voltage positive pole and extend the battery cycle life.

Substitute imports will appear high tide domestic membrane call for domestic materials

Sun dongquan, deputy secretary general of China plastics processing industry association and secretary of battery diaphragm committee of China plastics association, pointed out that as the world's largest producer of lithium batteries, China's demand for diaphragm is increasing day by day. In recent years, the growth rate of domestic diaphragm market demand is generally lower than that of domestic diaphragm, indicating that the market share of domestic diaphragm is rising, and the localization of diaphragm is the general trend.

However, China's current lithium battery diaphragm low-end market overcapacity, product prices are falling, payment days lengthening, but new investment projects are still in a steady stream, disorderly competition intensified. Although the import of high-end products is narrowing, the gap between domestic enterprises and leading foreign enterprises is still large. It is expected that the localization replacement of domestic high-end market will come to a climax in 2017-2018. In 2019, apart from a small amount of imports, more than 80% of the diaphragm will be localized.

Sun dongquan pointed out that the properties of PP or PE resin and other raw materials have a great impact on the performance of diaphragm. Domestic diaphragm enterprises in the material is still lack of real demand to meet the stability of the diaphragm material supply sources, product development is a long way to go. In terms of dry materials, sinopec Beijing institute of chemical industry has developed domestic lithium battery diaphragm materials, has been applied in the diaphragm enterprises; As for the special wet-process materials, sinopec Shanghai petrochemical research institute is developing the special wet-process lithium battery membrane materials, which will be promoted and tried in the future.

In terms of improving the performance of diaphragm, there are currently three ideas: one is to add functional coating on the basis of PP film and PE film to meet the special needs of high temperature characteristics. Second, the development of inorganic or organic materials blend PE, PP film; The third is to completely change the matrix material, such as the use of polyimide and other materials to replace the traditional PP and PE materials.

Zeng songjun, account manager of sinopec central China branch, pointed out that China's total annual demand for PP membrane materials is about 3.6 million tons, although the number of electrical film and packaging film is not large, but for a high technical content of the product is very considerable.

Many domestic enterprises once developed and produced low-end electrical film raw materials, but as the downstream users have higher and higher requirements for batteries, capacitors, etc., the demand for low-end products has dropped to about 20%, many enterprises due to technical and market capacity and other reasons, gradually abandoned the research and development and production of polypropylene capacitor film raw materials.

Wet-process membranes have long been used as raw materials for ultra-high molecular weight polyethylene, with thinner thickness (as low as 5 microns), higher strength, and more suitable for high-energy density batteries. But in fact, relevant enterprises can also be considered in PP raw materials, so that dry diaphragm can also ensure higher strength at the same time, lighter and thinner, more secure.

The page contains the contents of the machine translation.