动力电池外部短路故障热-力影响与分析

The safety of batteries has attracted much attention due to the frequent occurrence of electric vehicle safety accidents. The short circuit faults of batteries are considered to be the principal issues of most safety accidents. For the external short circuit faults, a cylindrical lithium-ion battery is taken as the research object, and according to the law of conservation of energy, a three-dimensional thermal model of the battery under the external short circuit condition is established. This model can be used to obtain the temperature distribution of the internal and external temperature of the battery. After that, a thermo-mechanical model is established. The heat stress distribution inside the battery is simulated and the results show that the maximum heat stress occurs in the contact part of the active material and the shell at both ends of the battery at 25 °C, and its trend with time is consistent with the surface temperature, and the peak heat stress of the battery at the low-stage SOC(state of charge) is rather large. The application of this model can provide a guiding role for the same type of battery saving test cost, structural optimization and reduction of heat stress to increase safety, and improve the understanding of the response law of the battery after external short circuit.