"In the process of moving towards high specific energy lithium-ion batteries, the current cost of producing batteries is gradually decreasing, the specific energy is rapidly increasing, and the driving range is gradually increasing. my country's electric vehicles have also taken a place in international competition. But in In this process, the safety issues of power batteries will become more prominent." Ouyang Minggao pointed out.

　　"With the continuous strengthening of national and local support for electric vehicles and the continuous improvement of the industrial environment, my country's electric vehicles have an eye-catching performance and have become the second largest market for production, sales and holdings after the United States." Zhao Zhao, Director of China Automotive Technology Research Center Aviation pointed out at the International Forum on Technology Innovation in Electric Vehicles held a few days ago.

　　Lithium electronic battery reaches its technological limit within 5 to 10 years

　　"In the process of moving towards high specific energy lithium-ion batteries, the cost of producing batteries is gradually decreasing, the specific energy is rapidly increasing, and the driving range is gradually increasing. my country's electric vehicles have also taken a place in international competition. But in In this process, the safety issues of power batteries will become more prominent." Ouyang Minggao pointed out.

　　He believes that the industrial foundation of China's electric vehicle battery technology is generally good. Since the Ministry of Science and Technology began to promote the research and development of electric vehicle power batteries during the "Tenth Five-Year Plan" period, the focus has shifted to ternary lithium ion. In the research and development of batteries, the specific energy of ternary lithium-ion batteries in my country will reach 180 watt-hours/kg in 2015. It is estimated that lithium-ion batteries will reach the technical limit in the next 5 to 10 years.

　　Compared with the world, China has many problems with electric vehicle power batteries. On the one hand, China’s research on advanced materials and mechanisms is poor, and the battery structure design technology is relatively low; on the other hand, the degree of automation is low, and the ability to develop refined processes is also weak. "In the past, we studied electric vehicles, thinking that the battery system only needs to be combined with the monomers, but now we understand that the battery system is a very complicated technology." Ouyang Minggao pointed out. In addition, the supply of high-end materials required for batteries is still insufficient, and the consistency, yield, safety, reliability, and product performance cannot fully meet market requirements. The overall innovation capability of the company is not strong, and the advantageous production capacity is insufficient. At the same time, China's electric vehicle power batteries are also facing challenges from foreign battery companies such as South Korea.

　　According to Ouyang Minggao's speculation, it is estimated that by 2025, lithium-ion batteries will be close to their performance limits, reaching about 350 watt-hours/kg to 400 watt-hours/kg. The U.S. Department of Energy judges the development status and trends of lithium-ion batteries that the battery limit can reach 300/kg to 350 watt-hours/kg, and at least about 200 watt-hours/kg by 2020. However, the current focus of technological research is how to solve the related problems of silicon anode to improve battery life.

　　Nowadays, the cost of pure electric vehicles mainly comes from the battery. From the perspective of balancing the range and cost, it is estimated that after 2020, electric vehicles with a range of 200 to 250 kilometers can compete with fuel vehicles. "But the safety, durability, and power of electric vehicles will be the three major technical problems, and the core is safety." Ouyang Minggao further emphasized.

　　On the other hand, Huang Hongsheng, chairman of Nanjing Jinlong Bus Manufacturing Co., Ltd., put forward a different view on the technical problems of power batteries. He believes that although power batteries have problems with energy density and safety, they are already very stable and have a long range. To solve travel problems, safety issues are no longer the biggest bottleneck.

　　Resolve security issues need to learn from foreign experience

　　However, it is an indisputable fact that there have been frequent fires of electric vehicles due to battery safety issues in recent years, which has made the majority of consumers who have doubts about electric vehicles even more resistant. The root cause is that factors such as overcharging, overheating, electrical triggering, and collisions may cause thermal runaway of the power battery. Ouyang Minggao said that the cause of thermal runaway is related to the unreasonable battery selection and thermal design, or the temperature rise of the battery caused by an external short circuit, or the loosening of the cable connector. It can be solved from two aspects of battery design and management, such as the development of materials to prevent thermal runaway to block the reaction of thermal runaway, etc. For battery management, different temperature ranges can be predicted first to define the safety level.

　　In addition, different batteries have very different safety levels. For example, in the event of a collision, the safety of lithium iron phosphate is higher than that of ternary lithium electronic batteries. "So up to now, we still insist on using lithium iron phosphate batteries in buses. It is not suitable for large-scale use of ternary batteries. Lithium electronic batteries, especially 12-meter buses." Ouyang Minggao said.