New energy vehicle 18650 rechargeable battery lithium 3.7v 3500mah face a battle over technical routes

　　China's new energy vehicles are developing rapidly, but the recent sudden change in the policy direction regarding its heart-power 18650 rechargeable battery lithium 3.7v 3500mah has brought huge uncertainty to the development of the industry.

　　According to statistics, sales of new energy vehicles in my country exceeded 300,000 units last year. For a pure electric vehicle, the battery cost accounts for nearly half of the total vehicle cost. At present, pure electric vehicle battery technology routes are generally divided into two types: ternary 18650 rechargeable battery lithium 3.7v 3500mah and lithium iron phosphate 18650 rechargeable battery lithium 3.7v 3500mah.

　　On January 14 this year, the Ministry of Industry and Information Technology released the "Catalogue of Recommended Models for the Promotion and Application of New Energy Vehicles". There is no ternary electric commercial bus in it, which means that models that are not included in the "Catalogue" will not be able to enjoy government subsidies and purchase tax exemptions ( 10%) policy discount. In this regard, Liu Yanlong, secretary-general of the China Chemical and Physical Power Supply Industry Association, said that the output and installed capacity of ternary material power lithium 18650 rechargeable battery lithium 3.7v 3500mah have been greatly affected. Once the risk assessment is completed and corresponding safety standards and measures are introduced, the industry will usher in new development opportunities.

　　Electric vehicle and battery manufacturers affected

　　Generally speaking, ternary materials have advantages in battery energy density, high-rate charging, and low-temperature performance, while lithium iron phosphate materials have long life and high safety. In December last year, an electric bus using ternary material power 18650 rechargeable battery lithium 3.7v 3500mah caught fire and exploded in Hong Kong.

　　Subsequently, at the China Electric Vehicle Hundreds Meeting on January 24 this year, Zhang Xiangmu, director of the Equipment Industry Department of the Ministry of Industry and Information Technology, said that the Ministry of Industry and Information Technology is organizing a risk assessment of ternary lithium battery buses and other models under the current safety standard system. Before the assessment is completed, , suspending the inclusion of ternary lithium battery buses in the catalog of recommended models for the promotion and application of new energy vehicles.

　　Liu Yanlong said that at this stage, the new energy vehicle industry relies on national policy subsidies to develop. The state's suspension of subsidies for ternary power battery buses has a great impact on the enthusiasm of car manufacturers.

　　Dr. Kirk, deputy director of the Research Institute of Chaowei Group, a leading company in my country's battery industry and a national expert, said in an exclusive interview with a reporter from Science and Technology Daily that Chaowei adheres to multiple technical routes and products of multiple specifications in parallel on the technical route of power lithium-ion 18650 rechargeable battery lithium 3.7v 3500mah. , among the power battery products put into the market in batches, there are both lithium iron phosphate battery systems and ternary material systems. However, before the suspension of the inclusion of ternary lithium battery buses in the catalog of new energy vehicle promotion and application models, Chaowei received orders also involving ternary materials. Therefore, corporate production plans will be affected to a certain extent.

　　The battle over battery safety

　　The Ministry of Industry and Information Technology has temporarily suspended ternary lithium 18650 rechargeable battery lithium 3.7v 3500mah, while other types of power 18650 rechargeable battery lithium 3.7v 3500mah such as lithium iron phosphate are not affected. Does this mean that 18650 rechargeable battery lithium 3.7v 3500mah such as lithium iron phosphate are safer than ternary material systems?

　　Kirk doesn't think so. He said that the safety of new energy vehicles and the safety of lithium-ion battery systems depends on a variety of factors including the lithium-ion battery cathode material system, not just the cathode material itself.

　　Also at the China Electric Vehicles 100-person Conference, Ouyang Minggao, professor of the Department of Automotive Engineering at Tsinghua University, reported the statistical results of safety accidents of new energy vehicles in China. The results show that the accident mainly comes from factors such as short circuit caused by collision, external short circuit caused by water intrusion into the battery, electrical connection failure, battery overcharging, and external short circuit caused by battery leakage.

　　Accidents such as the Shenzhen Wuzhoulong vehicle catching fire while charging and the Xiamen bus catching fire happened to be caused by lithium iron phosphate 18650 rechargeable battery lithium 3.7v 3500mah. This shows that the safety of individual materials does not represent the safety of the power battery system or the entire vehicle. Kirk said that the safety issue of power battery systems and new energy vehicles is a systemic issue. BMS (management system) strategy, vehicle control strategy, battery charge and discharge management, battery layout design and system manufacturing will all affect vehicle safety, and the single cathode material is only one of the factors.

　　Simply looking at the combustion or explosion mechanism of a lithium-ion battery accident, it is a so-called thermal runaway process. Kirk explained that firstly, various factors cause the internal temperature of the battery to rise. As the temperature rises, a series of processes will occur that further generate heat. The heat released by these processes cannot be discharged in time, causing the battery temperature to further rise, reaching The decomposition temperature of the positive electrode and electrolyte, and accompanied by the complete collapse of the separator and even the ceramic-coated separator, the temperature rises sharply, and eventually the battery violently burns or explodes.

　　The decomposition temperature of lithium iron phosphate is higher than that of ternary materials. The decomposition of ternary materials produces oxygen, which promotes subsequent thermal runaway. From this perspective, lithium iron phosphate is relatively safe. However, Kirk believes that from the perspective of the thermal runaway process, the thermal stability of the cathode material alone is not a decisive factor in the safety of lithium-ion 18650 rechargeable battery lithium 3.7v 3500mah. This is also proven by actual accident cases of complete combustion of buses using lithium iron phosphate 18650 rechargeable battery lithium 3.7v 3500mah.

　　The development of high energy density power battery systems is the mainstream trend

　　According to statistics, ternary 18650 rechargeable battery lithium 3.7v 3500mah currently account for more than 80% of the global lithium-ion battery market.

　　Kirk said that the development of high-energy-density power battery systems is a mainstream international trend. High-energy density is one of the core technical indicators of power 18650 rechargeable battery lithium 3.7v 3500mah in my country's 13th Five-Year Plan. This is also the current range of industrialized electric vehicles, which has not yet met market demand. inevitable result. The current international industrialized high-energy-density systems are mainly based on ternary systems.

　　Samsung and other companies' focus on the development of ternary 18650 rechargeable battery lithium 3.7v 3500mah is not a special case, but follows the international trend. The quality of the technical route itself should be judged more scientifically by the market itself. Kirk said.

　　At this year's Two Sessions, Zhang Tianren, deputy to the National People's Congress and chairman of Tianneng Group, also said that my country's high-end lithium battery industry cannot just be satisfied with state subsidies, but should rely on technological innovation, brand building, etc., especially in the ternary system, in the future it can compete with Samsung, Panasonic, etc. compete.

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