According to statistics from the Transportation Administration of the Ministry of Public Security of the People's Republic of China, as of the end of 2020, the number of new energy vehicles in the country has reached 4.92 million, of which 4 million are pure electric vehicles, accounting for 81.3% of the total number of new energy vehicles. The increase in new energy vehicles has exceeded 1 million units for three consecutive years, and the growth rate has been increasing year by year, indicating that the majority of automobile consumers have gradually understood, recognized, and accepted NEV, especially BEV, in terms of car purchase choices. But when it comes to EVs, safety is always a topic to be mentioned.

Statistics show that there were 61 spontaneous fire accidents reported in China in 2020. Most of the accidents were caused by power battery problems. The identified BEV reached 51, accounting for 84%, and there were 2 PHEVs, and 8 more. The power type of the accident vehicle is unknown. The cause of the fire is mostly concentrated in the power battery, in addition to the battery management strategy BMS, heat dissipation system, vehicle structure design and other comprehensive factors.

At present, in the field of electric passenger vehicles, power batteries are basically concentrated in two kinds of lithium iron phosphate batteries and ternary lithium batteries. Lithium iron phosphate battery has low cost, long cycle life and high safety, but its energy density is relatively low and the cruising range is short. The ternary lithium battery has high energy density and longer battery life, but safety is restricted. How to ensure the safety of the vehicle while taking into account the cruising range? It is necessary to work hard to improve the safety strategy of ternary lithium batteries.

At this stage, my country’s safety standards for electric vehicle power batteries are released on May 12, 2020 and will be formally implemented on January 1, 2021. This standard modifies and upgrades the previously implemented standards. It is stipulated in the appendix that “battery packs or systems shall provide a thermal event alarm signal 5 minutes before the heat dissipation caused by the thermal runaway of a single battery, which may cause danger to the passenger compartment. ". It can be seen from this that no matter what kind of power battery the new energy vehicle uses, it is necessary to give consumers sufficient time to save themselves when the battery is out of control. In addition, the regulations recommend acupuncture test method for the verification method of thermal diffusion occupant protection.

Last year, BYD announced the needling test of the blade battery and got good results, but it should be noted that the test object is a lithium iron phosphate battery, not a ternary lithium battery. Today, GAC Aion conducted acupuncture tests on the ternary lithium battery with its new power battery system safety technology.

According to the currently published information, the overall test project has achieved the set goals. Then, what is the core behind this test?

Why is it called a magazine battery?

Each battery cell is placed in a safe compartment, similar to a "magazine", with aviation-grade silica-grade high-temperature resistant nanomaterials in the middle, which has the characteristics of high temperature resistance and heat insulation, and is flame-retardant and heat-insulated to the greatest extent.

What is the core technology?

There are four core technologies: ultra-high heat-resistant and stable batteries, ultra-strong thermal insulation battery safety cabin, rapid cooling and three-dimensional rapid cooling system, and full-time control of the fifth-generation battery management system.

In the cathode material, nano-scale coating and doping technology is adopted, and the electrolyte realizes the self-repair of the SEI film through the application of new additives. At the same time, the use of all-tab laminations reduces the internal resistance by 10%, which can speed up heat dissipation. The integration of technology has increased the heat-resistant temperature of battery cells by 30%, forming a stable cell with ultra-high heat resistance.

In addition, the battery compartment adopts a super high-temperature-resistant upper shell, so that the overall temperature resistance of the battery safety compartment can reach above 1400°C, ensuring that adjacent batteries do not have thermal runaway.

In terms of the cooling system, the three-dimensional rapid cooling method is adopted, the liquid cooling integrated system is fully integrated, the high-efficiency heat dissipation channel design and the high-precision heat conduction path design are used to increase the heat dissipation area by 40% and the heat dissipation efficiency by 30%.

At the same time, it adopts a full-time management and control battery management system, using the latest generation of battery management chips, 10 times/second all-weather data collection, and 24-hour full coverage to achieve full-time management and control effects. If the system finds that a certain battery cell is abnormal, the system will start the self-rescue operation, start the quick cooling system for safe rescue, and reduce the temperature of the battery cell below the critical value of thermal runaway.

Why only do acupuncture tests?

Because the acupuncture test is the pinnacle of battery safety technology recognized in the industry. For the thermal diffusion test, there are two methods: acupuncture and heating. It is to simulate that after a short-circuit thermal abnormality occurs in one cell, it will not spread to the next cell to cause a series of thermal reactions. Then Aion’s solution is to detect and solve the problem in time after the first battery cell is found to be abnormal. Theoretically, the safety of the entire battery pack can be achieved.

The current situation and future product planning of GAC Aion

There are currently more than 100,000 Aion users across the country (including a certain percentage of operating vehicles), and the mileage exceeds 15 million kilometers per day. Manufacturers have provided solid data support for scientific research through the summary and analysis of massive battery operating data.

The magazine battery technology will be successively changed and carried on the Aion series in the future, and the first product is the upcoming Aion Y.

Will new technologies bring about product price fluctuations?

From my point of view, in the early stage of the emergence of relatively innovative technologies, there will definitely be a certain degree of improvement at the product level. This is a process that any product development will go through. After the number of product applications is spread out in a large area, it will inevitably spread the early stage. R&D expenses and product cost prices will also fall.

Summary: New technologies enhance new safety standards

Whether it is BYD's blade technology that was all the rage last year, or the current GAC Aion magazine battery technology, they are providing a safer environment and experience for car consumers. Among them, for the ternary lithium battery models with more advantageous mileage, the magazine battery technology of GAC Aion will theoretically greatly reduce the existing safety problems of electric vehicles (ternary lithium battery models) such as spontaneous combustion. The solution it provides is not Only staying at the change of the physical structure, but a complete set of packaging solutions for power batteries, to maximize the protection of consumers' personal and property safety. At the same time, the use of acupuncture tests that exceed the national standard test standards also provides a valuable reference for future revisions of related standards.