Investigation for the effect of side plates on thermal runaway propagation characteristics in battery modules

Abstract Side plates have been commonly arranged around lithium-ion batteries to ensure their structural stability when combining modules, which could affect the heat transfer path once thermal runaway propagation occurs in the battery modules, owing to the good thermal conductivity of side plates. However, the effect of side plates on the propagation characteristics is not comprehensively studied. In this paper, a validated three-dimensional thermal runaway propagation model of a battery module is used to investigate the propagation behaviors under different design schemes with side plates. A parametric study is carried out to determine the energy flow distribution of battery modules with and without side plates, and to evaluate the effect of the structural and thermal boundary parameters of the side plates on the failure propagation behaviors. The results indicate that the side plates delay the initial thermal runaway trigger time, considerably affect energy flow distribution, and aggravate the heat transfer. Approximately 40.8% of effluent energy passes through the side plates, dominating the critical point for battery thermal runaway propagation. Furthermore, with side plates surrounding the module, the initial thermal runaway trigger time is delayed by 12.7%, whereas the average propagation time interval between adjacent batteries is shortened by 27.4%, compared to those without side plates. An increase in the thickness, area, and aspect ratio of the side plates can postpone the initial thermal runaway trigger time, while shortening the average propagation time interval. This work adds new knowledge in the failure propagation mechanism within battery modules with side plates, enlightening the thermal safety design of high-energy battery modules.