Non-dimensional analysis of the criticality of Li-ion battery thermal runaway behavior

Highlights: • We give a further understanding of battery thermal runaway behavior and it's criticality. • Critical functions ($\psi$, $\delta$) and criteria (${\psi }_{cr},{\delta }_{cr}$) are proposed to analyze the criticality. • The critical models are revised by a weighted average of four exothermic reactions and reactant consumption. • The results of revised model compare well with those of simulated oven exposure tests. • The influence of cells modification and heat convection to battery criticality are analyzed quantitatively. -- Abstract: Lithium-ion batteries are the most popular used portable energy storage technology due to the relatively high energy density. While thermal instability induced safety concerns impede the pace of developing large scale applications, the practical applications have no tolerance for the catastrophic failure. To learn more about the characteristics of battery failure, the criticality of battery thermal runaway is studied in this paper. Semenov and Thomas models are employed to analyze the criticality of battery thermal runaway in uniform and nonuniform temperature distribution situations. In order to improve accuracy of prediction, the critical parameters of overall reaction are taken as a weighted average of four exothermic reactions and the critical criteria are revised by the consumption of reactants. Results from revised model are consistence with oven model. According to the revised thermal abuse models, the critical criterion (${\psi }_{cr},{\delta }_{cr}$) and critical temperature distribution (${\theta }_{\text{c}\text{r}}$) are analyzed in different composite materials, convective heat transfer coefficients and cell deformations. Results give the variation of critical criteria and critical temperature with these factors.