关键词: 锂离子电池, 热失控, 排气, 仿真

Abstract:

To investigate the diffusion process of injected gas after the thermal runaway of the lithium-ion battery for vehicles, the CONVERGE CFD model was selected to simulate the gas injection of the thermal runaway cell of the square ternary lithium-ion battery under the 100% SOC state. The diffusion law of thermal runaway gas inside the battery pack, the accumulation situation, and the gas mass flow characteristics at the battery pack exhaust port under the four schemes were analyzed using the tracer particle labeling method. The research results show that the thermal runaway gas diffuses to the top of the box when it is sprayed for 4.3 s. The gas gradually spread to the surroundings after accumulating at the top of the box. The gas can diffuse to the upper half of the entire box at the fastest 22.3 s. The position of the upper exhaust port affects the diffusion and accumulation of gas within the battery pack. A comparison of the four schemes reveals that setting the exhaust port on the upper part of the box and increasing the number of exhaust ports will aid in the discharge of gas from the battery pack, reducing the accumulation of internal gas; solely relying on the exhaust port will not deplete all the thermal runaway gas in the box, and obvious gas accumulation can be observed in the battery pack's inner corner.

Key words: lithium-ion battery, thermal runaway, gas vent, simulation