Performance and safety protection of internal short circuit in lithium-ion battery based on a multilayer electro-thermal coupling model

Internal short-circuited lithium-ion battery can generate much heat in a short time and that leads to local high temperature or even explosion. A multilayer electro-thermal coupling model considering the interplay of current at different positions is developed to study the performance of internal short circuit and penetration before the trigger of thermal runaway. The simulation result agrees with the experiment in a certain extent. This study will serve as a guideline for protective design of internal short circuit. It concludes that penetration is not a precise method to simulate the performance of one-layer internal short circuit from view of maximum temperature and effect of cell unit layers. Temperature of large capacity battery is higher relatively when internal short occurs. A new method, in which the battery is forced to external short circuit when the internal short circuit is detected, is proposed to protect the battery from internal short circuit. The battery is within safe range if the external short circuit resistance is small enough. More, the maximum temperature increases with the decrease of battery resistance. Decreasing the resistance may increase the thermal runaway risk while increasing the battery resistance is a good protective method.