Experimental study of explosion parameters of hybrid mixture caused by thermal runaway of lithium-ion battery

The explosion characteristics of the runaway battery vented gas (BVG) was studied using an 8 L column type device. The effects of ambient temperature, turbulence condition, and graphite dusts-ejected along with the BVG on the explosion process-were investigated. At 25 & DEG;C, the explosion limits of pure BVG, the maximum explosion pressure (Pmax), and the maximum rate of explosion pressure rise (dP/dt)max is 10.8-45.8% by volume, 0.62 MPa, and 37.6 MPa/s, respectively. At 80 & DEG;C, the three parameters changed to 10.4%- 46.5%, 0.49 MPa and 35.5 MPa/s. Moreover, these three parameters changed to 10.2-47.5%, 0.45 MPa and 33.3 MPa/s at 120 & DEG;C. The increase in temperature reduced Pmax of BVG. While turbulence had little effect on the explosion pressure of BVG, it has significantly affected the dP/dt value. Adding graphite dusts helps BVG get to Pmax at a much lower volume concentration. As temperature increased, this effect became greater. Also, the graphite dusts can reduce the time of BVG to attain the Pmax value after igniting - the maximum reduction is from 325 ms to 158 ms. As ambient temperature increased, the combustible gas molecules were reduced, resulting in a lower Pmax value. The heat released from the BVG explosion drives the graphite involving dust explosion when oxygen is excessive. The above findings can provide a reference for the prevention of environmental explosions caused by the thermal runaway of lithium-ion batteries in process industry.

Automated summary

The explosion characteristics of runaway battery vented gas (BVG) were studied, and the effects of ambient temperature, turbulence conditions, and graphite dust were investigated. The temperature increase reduced the maximum explosion pressure of BVG, while turbulence had little effect on explosion pressure but significantly affected the rate of explosion pressure rise. Adding graphite dusts helped BVG reach the maximum explosion pressure at a lower volume concentration and reduced the time to reach the maximum pressure after ignition.