01It has become an industry consensus to attach great importance to the development of safe batteries

 In recent years, with the continuous popularization of electric vehicles, the number of recalls involved in the world has also shown an increasing trend. The responsible parties of the recall include Hyundai, GM , Volkswagen, Tesla, WM Motor, BAIC, LG New Energy, Samsung SDI and other domestic and foreign mainstream OEMs and battery companies. In particular, South Korean battery giant LG New Energy was caught in the whirlpool of recalls and paid high compensation due to frequent battery safety issues, resulting in heavy losses. The successive recalls of LG New Energy have also sounded the alarm for the entire battery industry, and it is imminent to further improve the safety of lithium batteries. At present, a number of battery companies and automobile companies have started an "arms race" for battery safety, and have launched "no fire" solutions.

 Battery safety technology introduced by some battery companies and auto companies

 In addition, power battery safety has become a new concern for consumers. According to Deloitte Consumer Research, among the main factors that Chinese consumers pay attention to electric vehicles, safety accounts for 29%, accounting for a relatively high proportion. In addition, from the perspective of the proportion of electric vehicle quality complaints, battery complaints accounted for 37.1%, including power battery failure, charging failure, battery failure, etc. The survey results provide a strong decision-making basis for the development of battery companies and OEMs. Battery safety has also become a new round of publicity points for auto companies in addition to battery life and fast charging. From the perspective of consumers, improving the safety of lithium batteries is conducive to safeguarding their legitimate rights and interests, boosting consumer confidence and stimulating consumption potential.

 02The current new features to improve the safety of power lithium batteries

 Reduce the risk of battery thermal runaway: The new battery technology innovates from three aspects: intrinsic safety, passive safety, and active safety. One is intrinsic safety. That is, starting from the thermal runaway mechanism of the single battery, improving the thermal stability of each cell material at the material level, and ensuring the reliability of the cell from the perspective of design and manufacturing at the process level. For example, the "sandwich safety battery" developed by OPPO uses a composite current collector instead of a traditional current collector, which is not easy to break, so as to solve the safety problem of high nickel ternary. The second is passive safety. That is, after the thermal runaway of a single cell, the heat spread is suppressed by means of heat insulation and heat dissipation. For example, the "magazine battery" developed by GAC Aeon, and the "amber" and "mica" batteries released by Lantu Automobile all focus on deepening thermal insulation solutions. The third is active safety. Its core is the battery management system (BMS), which provides early warning of thermal runaway through technologies such as big data. For example, the "100kWh battery" released by NIO integrates a thermal runaway sensor in the BMS, which can monitor thermal pressure in real time for 24 hours, thereby improving battery safety.

 Various technical routes are developing simultaneously: lithium iron phosphate and ternary are the mainstream, and large cylindrical batteries have attracted much attention. In terms of battery materials, lithium iron phosphate and ternary are the mainstream in my country. Due to the abundant sources of lithium iron phosphate materials, high safety, low cost, and good cycle performance, the market demand for lithium iron phosphate batteries has increased in recent years, and shipments have grown explosively. According to statistics, the installed capacity of lithium iron phosphate and ternary lithium batteries will account for 53% and 47% respectively in 2021, completely reversing the trend that the output of lithium iron phosphate batteries has been lower than that of ternary lithium batteries since 2018. In addition, lithium titanate, lithium manganate, etc. have been used to some extent. In terms of battery form, the current power battery market has formed a three-dimensional situation of square shell/blade, soft pack, and cylinder. With the advantages of high safety, high energy density and low cost, large cylindrical batteries are becoming the most attention. one of the technological trends. Combined with the actual needs of the whole vehicle, many electric vehicle companies have finalized the power battery plan for the next 5-10 years, that is, the economical type adopts square shell or blade lithium iron phosphate battery, and the middle and high-end adopts the layout of ternary + large cylindrical battery.

 03Strengthen the top-level design, focusing on three aspects of lithium battery safety

 Strengthen joint technical research and achieve cross-industry collaboration and integration. The safety of lithium batteries is an extremely complex and systematic issue, which involves not only material research, but also issues such as technology application and structural optimization. Safety issues have gradually extended to upstream and downstream industrial chains and border areas of cross-industry integration. Recommendations: First, continue to tackle key lithium battery safety technologies. Adhere to the two routes of lithium iron phosphate and ternary, carry out research on key material technologies such as solid electrolyte and flame retardant electrolyte, and speed up the thermal runaway safety of power batteries, high-voltage insulation safety and crash safety of battery systems, and thermal stability of ternary material power batteries. , charging safety protection and other safety technology research. The second is to give full play to the superimposed advantages and organize cross-industry collaborative research. Actively carry out the coordination between battery companies and vehicle companies, and carry out in-depth cooperation in the design stage, vehicle matching, thermal management strategies, abnormal state monitoring, testing and verification, etc.; strengthen the coordination between battery companies and the fire protection industry, focusing on power battery fire cases Conduct exchanges and joint research on analysis, early fire detection of power battery thermal runaway, long-term fire extinguishing agents, and automatic fire extinguishing devices.

 Strengthen the construction of lithium battery testing capabilities to ensure a sufficient testing and verification cycle for products before mass production. Insufficient testing and verification before mass production of batteries has become a prominent problem restricting the development of the industry. On the one hand, some companies blindly pursue high specific energy in order to obtain subsidies, shorten the test and verification time, and cut the battery development and verification period of at least three years by half. On the other hand, the battery test and verification methods are not perfect, and even some companies do not have the ability to test battery safety. Recommendations: First, keep the technical conditions of the subsidy policy appropriately stable. The setting of indicators such as electric vehicle access and subsidies should conform to the laws of technological development, and should not be changed frequently. If there are changes, companies should be given at least two or three years to develop, design, and verify new products. The second is to strengthen battery testing capacity building. Improve the testing system that combines enterprise independent testing, public service testing and national certification testing. Encourage battery manufacturers, electric vehicle manufacturers, research institutions, and testing and certification institutions to strengthen the accumulation of relevant data such as product testing and verification, and lay a solid foundation for product development, standard formulation and revision, and product consistency control.

 Improve the construction of lithium battery safety standard system, and further improve the battery thermal runaway alarm and safety protection level. At present, my country's power lithium battery safety standard requirements and related test procedures are mainly aimed at fresh power batteries, but studies have shown that the middle and late stages may be the "high incidence period" of thermal runaway reaction of power batteries, which requires special prevention and control. Recommendations: First, speed up the formulation and revision of lithium battery safety standards. Improve the whole life cycle safety testing standards of power battery cells, modules and systems to make up for the deficiencies of existing standards; for the definition and description of phenomena such as leakage, shell rupture, fire, explosion, etc. used in the current standards for battery testing Relatively broad phenomenon, strengthen the judgment basis of quantifiable test results. The second is to carry out more stringent research on safety and quality standards. For example, as a very effective and harsh method in lithium battery testing, acupuncture test is recommended to be gradually incorporated into national mandatory standards. The third is to promote the process of internationalization of standards. Accelerate the transformation of international standards, and actively promote the mutual recognition and sharing of inspection and testing results. Support industry organizations and enterprises to actively participate in the formulation of international standards and technical regulations, and continuously enhance my country's international voice.