Thermal Runaway Triggered by Plated Lithium on the Anode after Fast Charging.

Abstract

Battery safety at the background of fast charging is critical on the application of lithium-ion batteries, especially for high energy density cells applied in electric vehicles. In this paper, an earlier thermal runaway of cells after fast charging applies is illustrated. Under this condition, the reaction between the plated lithium and electrolyte is revealed to be the mechanism of thermal runaway triggering. The mechanism is proved by the accelerated rate calorimetry tests for partial cells, which determine the triggering reactions of thermal runaway in the anode-electrolyte thermodynamic system. The reactants in this system is analyzed by nuclear magnetic resonance and differential scanning calorimetry, proving that the vigorous exothermic reaction is induced by the interaction between the plated lithium and electrolyte. As a result, the finding of thermal runaway triggered by the plated lithium on anode surface of cells after fast charging promotes the understanding of thermal runaway mechanisms, which warns us the danger of the plated lithium in the utilization of lithium-ion batteries.