Overcome the safety problem of ternary lithium battery and create the safety technology of "no fire" battery system
At present, lithium iron phosphate battery and ternary lithium battery are two mainstream battery technology routes in the global electric vehicle industry. Lithium iron phosphate battery is widely used in medium and low endurance vehicles because of its longer life and lower cost. Because of its high energy density and low power consumption, ternary lithium batteries are mainly used in medium and high endurance vehicles. According to the actual use of the current market, lithium iron phosphate batteries and ternary lithium batteries will continue to develop in parallel for a long time to come. The safety of lithium iron phosphate battery has been relatively recognized, but the safety of ternary lithium battery is still recognized as a pain point and difficulty in the industry. Enterprises related to the industrial chain of new energy vehicles are also carrying out research on battery safety technology. "Fireless" battery technology is the most important and difficult fortress for battery safety.
In order to verify the safety of the magazine battery, Dr. Liu Shiqiang, the chief expert of China Automotive Technology and Research Center and one of the drafters of the national battery safety standards, led the team to carry out the needle thermal diffusion test of the ternary lithium battery equipped with the safety technology of the magazine battery system. The test results show that the ternary lithium (magazine battery) package of GAC Ai 'an only smokes briefly (1 min) five minutes after the thermal accident signal is sent out, and there is no fire and explosion. After standing for 48 hours, the voltage dropped to 0V and the temperature returned to room temperature. After acupuncture, only the stabbed battery module was out of control and did not spread to other batteries. Open the battery package and observe whether the internal structure is intact. This is the first time in the industry that the whole package of ternary lithium battery has passed the flameless acupuncture test, and the safety of ternary lithium battery has made a historic breakthrough.
Safety goes beyond "core" and sets a new benchmark for battery system safety.
Nowadays, the understanding of vehicle safety in electric vehicle industry has changed from single safety to system safety, and improving the safety performance of battery pack has become the mainstream trend in the industry.
At present, the spontaneous combustion of batteries is mostly caused by the internal short circuit of the battery cell, which leads to the temperature rise, and the heat generated by the internal reaction of the battery cell eventually gets out of control, and then spreads to the whole battery pack. Battery safety solves the intrinsic safety of the battery, while the whole package safety solves the all-round safety from battery, module to system with systematic thinking, which is more important and more difficult to realize than battery safety.
Guangzhou Automobile Aian's magazine battery is a systematic technology to improve the safety of power battery. It is not a simple structural optimization, nor a simple increase in heat insulation, but a set of safety technologies from the intrinsic safety of batteries to passive safety enhancement, and then to the active prevention and control of software. It is also an intelligent security technology integrating software and hardware, with super high defense capability.
Based on the design idea of "preventing short circuit in the battery core, preventing thermal runaway after short circuit and preventing thermal diffusion after thermal runaway", the magazine battery adopts a design similar to a safety cabin, which can effectively block the diffusion of the thermal runaway battery, and automatically start the battery rapid cooling system to cool the battery when the battery voltage or temperature is abnormal.
Magazine batteries have four core technologies:
First, ultra-high heat-resistant and stable batteries. The battery core can effectively improve thermal stability and prevent thermal runaway through the application of cathode material nano-coating and doping technology; The application of new additives in electrolyte realizes the self-repair of SEI membrane, thus improving the battery life and reducing the risk of battery short circuit. The high-safety electrolyte is heated to above 120℃ by special electrolyte additives, and spontaneously polymerizes on the surface of active materials to form a high-impedance polymer film, which greatly reduces the heat generated by thermal runaway reaction. The application of these key technologies has improved the heat-resistant temperature of batteries by 30%.
Second, the super-insulated battery safety cabin. Through the reticulated nano-porous thermal insulation material and the high-temperature resistant upper shell, the super-thermal insulation safety cabin is constructed by the magazine battery, which finally realizes that the battery core of ternary lithium battery is out of control and does not spread to adjacent batteries, and at the same time, the upper shell of battery package can bear the temperature above 1400℃, thus effectively protecting the whole battery package.
Third, the rapid cooling system of rapid cooling. Through the design of full-fit liquid cooling system, high-speed heat dissipation channel and high-precision heat conduction path, the heat dissipation area of magazine battery is increased by 40%, the heat dissipation efficiency is improved by 30%, and the heat diffusion is effectively prevented.
Fourth, the fifth generation battery management system with full-time control. By using the latest generation battery management system chip, the magazine battery can achieve 10 all-weather data acquisition every second, which is 100 times higher than the previous generation system. Monitor the battery status in full-time patrol mode with 24-hour full coverage. When any abnormality is found, immediately start the battery rapid cooling system to cool the battery. The full-time patrol mode and the application of abnormal self-rescue redefine the standard of active safety of ternary lithium batteries.
Although a large number of safety designs have been added to the magazine battery, at the same time, the heat dissipation system, cell design and overall packaging layout have been comprehensively optimized. The energy density and volume of the battery pack equipped with the safety technology of magazine battery system increased by 9.4%, the weight increased by 5.7%, and the cost decreased by 10%. Therefore, the safety technology of magazine battery system realizes high safety, long battery life and low cost without sacrificing battery life and increasing cost.
Long-term R&D investment and technology accumulation have created more than 80 invention patents.
The reason why Guangzhou Automobile Aian can make a major breakthrough in the field of battery safety is mainly due to the long-term resource investment and technical accumulation of Guangzhou Automobile in electrification technology. As early as 20 1 1, GAC began the research and application of electrification technology, and launched the first medium and heavy hybrid vehicle in China. In the research of electrification technology, the research and development of GAC has been more than 10 years, forming a large number of technical achievements and talent reserves.
The magazine battery is jointly developed by Guangzhou Automobile Research Institute, Guangzhou Automobile Silicon Valley R&D Center and the world's top battery experts. The top international R&D team composed of more than 600 people, including more than 60 doctors, has made great efforts to build it, which reflects the highest technical level of battery safety in Guangzhou Automobile Aian. Guangzhou Automobile has carried out research and development from the aspects of over-current protection of power batteries, methods for restraining battery heating, monitoring and early warning of battery thermal runaway, etc., and has formed a leading international patent group, including more than 80 patents, accounting for more than 70% of inventions. It provides a solution for the healthy and sustainable development of the new energy automobile industry.
At present, GAC has the leading battery laboratory, professional test field and battery pack production workshop in the industry, and has the ability to independently design and manufacture battery packs. After continuous iterative optimization, the BMS battery management system independently developed by GAC has been upgraded to the fifth generation and applied to magazine battery technology. At the same time, AION series products have more than 65,438+million users, and generate more than150,000 kilometers of mileage every day, which brings massive battery operation data and provides solid data support for the research and development of magazine batteries. System-level battery safety technology has become the unique advantage and strength of Guangzhou Automobile Aian.
"Magazine battery" will be carried on all AION models one after another this year, and the brand initial intention of AI accompanying mobile travel will be practiced.
The publication of "Battery System Safety Technology" by Guangzhou Automobile Aian Magazine is a milestone, which indicates that battery safety has risen to a new height. In particular, the safety of ternary lithium batteries has made a historic breakthrough and redefined the safety standard of ternary lithium batteries, which is of great significance to the development of global new energy automobile industry. Guangzhou Automobile Aian once again brings "advanced technology enjoyment" to customers with world-class innovative technology.