Investigation of Short-Circuit Scenarios in a Lithium-Ion Battery Cell

A short-circuited lithium-ion battery cell is likely to generate sufficient heat to initiate exothermic side reactions causing thermal runaway. A 2D coupled electrochemical-thermal model was developed to investigate a prismatic LiNi0.8Co0.15Al0.05O2 vertical bar LiPF6, EC/EMC (3:7)vertical bar MAG-10 battery cell that is short-circuited. Three short-circuit scenarios are investigated during the events from when short circuit occurs until exothermic side reactions initiate. The scenarios are an external short circuit, a nail penetration and an impurity-induced short circuit. The model is used to predict the temperature increase within the cell and to explain how the interrelation between the electrochemical processes and the thermal properties affects the increase. Important safety measures are also examined with the model. The simulation results highlight general short-circuit characteristics and critical distinctions between the scenarios. The mass transport of lithium ions in the electrolyte is found to be the most important general characteristic that determines the rate of the temperature increase. The electric resistance distinguishes the scenarios from each other. The rate of the temperature increase is dictated by the mass transport in the electrolyte even when large variations in available active material are made and it is shown to be difficult to slow down the rate by cooling. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.096206jes] All rights reserved.