On March 10, GAC Ean released a new generation of power battery safety technology-magazine battery system safety technology (hereinafter referred to as "magazine battery"), named for placing the battery in a safety cabin shaped like a magazine. This technology improves the safety of power battery from the four latitudes of cell material, battery structure, cooling system and battery management system, and there is no fire and explosion in the whole package of acupuncture test. It is reported that magazine battery technology can be used in lithium iron phosphate and ternary lithium battery packages, and power batteries equipped with this technology will be installed on all AION models this year.
How does magazine battery improve battery safety?
The fire and explosion of the battery is often caused by the short-circuit heating inside the cell, which causes the heat to get out of control and spread to the whole battery package. Aiming at this problem, magazine battery optimizes the battery material, battery package structure and battery management system, and uses a systematic scheme to solve the safety problem of power battery. Through the comprehensive optimization of the cooling system, cell design, package layout and other aspects, the magazine battery not only improves the safety, but also does not sacrifice the battery life or increase the cost. Guangzhou Auto EA official said that compared with similar ordinary battery packages, the energy density of the battery pack equipped with magazine battery technology increased by 9.4%, the weight energy density increased by 5.7%, and the cost decreased by 10%.
In terms of the safety of the cell, the magazine battery uses nano-scale coating and doping technology in the positive electrode of the cell, which not only ensures the activity of the positive electrode with high nickel, but also further improves the thermal stability of the cell. Two new additives are added to the electrolyte, which can realize the functions of self-repair of diaphragm and reducing heat production of thermal runaway reaction. According to the official information released by GAC EA, the application of these new technologies has increased the heat-resistant temperature of the cell by 30% and improved the cell's ability to resist thermal runaway.
If the cell has been thermal out of control or overheating, then it is necessary to control the spread of thermal runaway through the structural design of the battery. Magazine battery technology uses reticulated nano-hole thermal insulation material and high temperature resistant upper shell to isolate heat conduction and prevent the thermal runaway of the battery from spreading to other surrounding cells and even to the whole battery package. At the same time, the newly designed full-fit liquid cooling system also makes the magazine battery have higher heat dissipation area and heat dissipation efficiency, and the temperature control of the cell is more timely and effective, which can significantly reduce the core temperature and the degree of damage caused by thermal runaway.
In the supervision of battery status, the magazine battery is equipped with GAC's fifth-generation battery management system, which can achieve 10 times per second, 24 hours uninterrupted data collection, real-time monitoring of the health status of the battery pack, it can be said to prevent "unburned". When an anomaly is found, it can immediately start the battery quick-cooling system to cool the battery to "self-rescue".
What is acupuncture thermal diffusion test? How did the magazine battery perform in the test?
At the press conference, GAC Ean also passed the acupuncture thermal diffusion test to verify the safety of the ternary lithium battery pack using magazine battery technology. In the test, a steel needle with 8mm diameter is used, and the battery pack is charged to a fully charged state. The thicker the steel needle is, the more serious the internal short circuit of the cell is, the more full the energy is, and the more severe the heat is out of control. By piercing the steel needle into the inside of the battery package, causing the battery internal short circuit, and then promoting the thermal runaway of the power generation pool, the safety of the battery package can be tested in practice.
In the test, although the highest temperature of the cell unit reached 686.7 ℃, the ternary lithium battery pack equipped with magazine battery technology only briefly smoked 5 minutes after sending out the thermal accident signal, and there was no fire or explosion, which met the requirement of GB 38031-2020 "Safety requirements for Power Storage Battery for Electric vehicles" that the battery unit could not catch fire and explode within 5 minutes after thermal runaway. The escape time was set aside for the crew. After 48 hours of rest, the voltage of the stinging cell has dropped to 0V and the temperature has returned to room temperature. At this time, open the battery pack to observe that the internal structure is still intact, only the stinging cell module appeared the phenomenon of thermal out of control, did not spread to other cells. Thus it can be seen that the magazine battery technology has played an obvious role in restraining the scope and harm of thermal runaway.
