Experimental study on the runaway behaviors of Panasonic 21,700 LiNi0.8Co0.15Al0.05O2 battery used in electric vehicle under thermal failure

Thermal runaway phenomena of the Panasonic 21,700 LiNi0.8Co0.15Al0.05O2 lithium-ion batteries with 100, 50 and 25% capacity were studied under thermal abuses. Characteristic data of onset temperature, crucial temperature, maximum self-heat rate, maximum temperature and maximum pressure are determined and affirmed for hazard analysis. The maximum temperature could be as high as 1200 degrees C exceeding the auto-ignition temperature of electrolyte to ignite the flammable vapors exposed to the air. Maximum self-heat rates are determined to be as high as 64,536 degrees C min(-1). Runaway behaviors with respect to the capacities of 50% and 25% are performed in comparison with those of 100%. Thermal runaway consequences possessed by the Panasonic 21,700 LiNi0.8Co0.15Al0.05O2 with the capacity of 25% cannot be indiscreet because its maximum temperature is approximately 600 degrees C with a maximum self-heat value of 10,000 degrees C min(-1) and an 110 mmol non-condensable gases generated. Differences in runaway behaviors are compared between the 21,700 and 18,650 LiNi0.8Co0.15Al0.05O2 batteries with the same capacity of 100%.