New energy vehicle batteries face the dispute over technical routes

my country's new energy vehicles are developing rapidly, but the recent sudden changes in the policy winds about their heart-powered lithium batteries have brought huge uncertainty to the development of the industry. According to statistics, the sales of new energy vehicles in my country exceeded 300,000 vehicles last year. For a pure electric vehicle, the battery cost accounts for nearly half of the vehicle cost. At present, the battery technology route of pure electric vehicles is roughly divided into two types: ternary battery and lithium iron phosphate battery. On January 14 this year, the Ministry of Industry and Information Technology announced the 'Catalog of Recommended Models for the Promotion and Use of New Energy Vehicles'. There is no ternary electric commercial bus, which means that models that have not entered the 'Catalog' will not be eligible for government subsidies and exempt from purchase tax (10%) policy concessions. In this regard, Liu Yanlong, secretary general of my country's Chemical and Physical Power Supply Industry Association, said that the output and installed capacity of ternary materials power lithium-ion batteries have been greatly affected. Once the risk assessment is completed and the corresponding safety standards and measures are issued, the industry will usher in new development opportunities. Electric vehicles and battery processing companies are affected. Generally speaking, ternary materials have advantages in battery energy density, high-rate charging, and low-temperature performance, while lithium iron phosphate materials have a long life and high safety. In December last year, an electric bus using ternary materials powered lithium batteries caught fire and exploded in Hong Kong. Subsequently, at the my country 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-ion battery buses and other models under the current safety standard system. Before the evaluation is completed, the suspension of the ternary lithium-ion battery bus will be listed in the catalog of recommended models for the promotion of new energy vehicles. Liu Yanlong said that at this stage, the new energy automobile industry has been developed by relying on national policy subsidies. The state's suspension of subsidies for ternary power lithium battery buses has a great impact on the enthusiasm of automakers. Dr. Kirk, vice president of the research institute of Chaowei Group, a leading company in the battery industry in my country, said in an exclusive interview with a reporter from Science and Technology Daily that Chaowei adheres to multiple technical routes and parallel products with multiple specifications on the technical route of power lithium-ion batteries. , Among the power lithium battery products put on the market in batches, there are not only lithium iron phosphate battery systems, but also ternary material systems. However, before the suspension of ternary lithium-ion battery buses from being included in the catalog of new energy vehicles to promote the use of models, Chaowei also received orders for ternary materials. Therefore, the company's processing plan will be affected to a certain extent. The dispute over battery safety The Ministry of Industry and Information Technology temporarily suspends ternary lithium-ion batteries, while other types of power lithium batteries such as lithium iron phosphate are not affected. Does this mean that batteries such as lithium iron phosphate are safer than the ternary material system? Kirk thinks otherwise. He said that the safety of new energy vehicles and the safety of lithium-ion battery systems depend on a variety of factors including the positive electrode material system for lithium-ion batteries, not just the positive electrode material itself. Also at the my country Electric Vehicle Hundreds Meeting, Professor Ouyang Minggao of the Department of Automotive Engineering of Tsinghua University reported on the statistical results of my country's new energy vehicle safety accidents. The results showed that the accident mainly originated from factors such as short circuit caused by collision, external short circuit caused by water ingress of the battery, electrical connection failure, battery overcharge, and external short circuit caused by battery leakage. Accidents such as Shenzhen Wuzhoulong's vehicle catching fire while charging, Xiamen bus catching fire and other accidents are precisely lithium iron phosphate batteries, which shows that the safety of single materials does not represent the safety of the power lithium battery system or the entire vehicle. Kirk said that the safety issue of power lithium 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 burning or explosion mechanism of a lithium-ion battery in an accident, it is a so-called thermal runaway process. Kirk explained that, firstly, the internal temperature of the battery rises due to various factors. As the temperature rises, a series of processes that further lead to the initiation of heat will occur. The heat released by these processes cannot be discharged in time, causing the battery temperature to rise further. The positive electrode and the electrolyte analyze the temperature, and with the complete collapse of the diaphragm and even the ceramic-coated diaphragm, the temperature rises sharply, and the battery burns or explodes violently. The analysis temperature of lithium iron phosphate is higher than that of ternary materials, and the oxygen generated from the analysis of ternary materials is useful for subsequent thermal runaway. From this perspective, lithium iron phosphate is relatively safe. But Kirk believes that from the perspective of the thermal runaway process, the thermal stability of the positive electrode material alone is not a decisive factor in the safety of lithium-ion batteries. The actual accident case of the complete combustion of a passenger car with a lithium iron phosphate battery also proves this. The development of high-energy-density power lithium battery systems is the mainstream trend. According to statistics, ternary batteries currently account for more than 80% of the global lithium-ion battery market. Kirk said that the development of high-energy-density power lithium battery systems is an international mainstream trend. High-energy density is one of the core technical indicators of power lithium batteries in my country’s 13th Five-Year Plan. This is also the current industrialized electric vehicle cruising range, which is still unsatisfactory. The inevitable result driven by market demand. The current high energy density system of international industrialization is mainly based on ternary. Samsung and other companies focus on the development of ternary batteries is not a special case, it is closely following the international trend. The pros and cons of the technical route itself should be judged more scientifically by the market itself. Kirk said. At the two sessions this year, Zhang Tianren, deputy to the National People’s Congress and chairman of Tianneng Group, also stated that my country’s high-end lithium-ion battery industry should not only be satisfied with state subsidies, but should rely on technological innovation, brand building, etc., especially in terms of the ternary system. Compete with Samsung and Panasonic.