202 1, Great Wall Science and Technology Festival at the end of June
Based on the current development goal of energy saving and emission reduction, electric vehicles have become the development trend of the industry, and consumers also have great demand for them. Safety is the main factor affecting consumers' car purchase. In order to solve the thermal runaway problem of ternary battery, Dayu battery adopts the design concept of "changing blockage into sparse", including "heat source isolation, bidirectional commutation, heat flow distribution, directional explosion removal, high temperature insulation, automatic fire extinguishing, positive pressure oxygen blocking and intelligent cooling", which mainly covers the fields of heat source suppression, isolation, cooling and discharge.
In the technical principle of "control+conduction = conduction" of Dayu battery, control refers to battery core insulation, module-level insulation and comparison of insulation materials, and guidance refers to flame-retardant design of fire box and directional explosion discharge of package. Finally, explosion venting, cooling and heat conduction are realized through four aspects: directional explosion venting flow field, temperature field, fire box and conduction heat transfer, and the gas-fire flow is safely led out of the battery pack according to the designed channel, thus solving the problem of fire and explosion caused by thermal runaway.
The technical advantage of Dayu battery is that it can realize "full coverage of battery cell chemical system", "battery at any position" and "single battery or multiple batteries", and the whole package will not catch fire and explode under the condition of out-of-control heat. According to the needs of different models, the R&D team of Great Wall Motor is diversifying the application of Dayu battery technology to batteries with medium nickel, high nickel, cobalt-free and lithium iron.
At the same time, Great Wall Motor also made a strict thermal runaway test on Dayu battery, according to the test standard: GB 3803 1-2020? "Safety Requirements for Power Batteries for Electric Vehicles" selects ternary 8 1 1 system high-nickel large-capacity batteries and tests them by heating trigger. During the test, two batteries are triggered continuously, and the battery in the middle of the module is selected as the trigger position.
During the test, thermal runaway was triggered by the accumulation of multiple batteries for three consecutive times, and the highest temperature reached 1037℃. The air pressure in the battery pack reaches three peaks, and the instantaneous maximum air pressure is about 16kPa. The maximum temperature for suppressing the smoke overflowing from the battery pack by the fire extinguishing system is lower than 100℃, so as to avoid secondary damage to the surrounding area.
In addition to Dayu battery itself, Great Wall Motor also brought the first all-inclusive thermal runaway combustion model, which can realize multi-dimensional fitting simulation of airflow and fire flow, avoid the traditional way of developing first and then testing in the field of thermal runaway, better grasp the safety design results of the battery, and shorten the development cycle and risk.
At present, the practical application of Dayu battery is not far away. As the next generation of brand-new power battery technology, Dayu battery technology is planned to be fully applied in 2022, and the first project is the first model of Salon brand. Salon is a high-end brand of new energy vehicles under Great Wall Motor, and it will come to the public soon in the future.
202 1, Great Wall Science and Technology Festival at the end of June
It is noteworthy that Great Wall Motor announced that dozens of patents of Dayu battery technology will be open to the whole society free of charge, promoting the development of new energy vehicles.