Optimization design and temperature control performance research of phase change material thermal management system for electric vehicle battery pack

To solve the problems of low thermal conductivity and uneven temperature distribution of PCM in thermal management of electric vehicle power batteries, this paper proposes a triple innovative solution: constructing efficient thermal conduction paths with 3-D graphene networks, designing regional phase change units with honeycomb structures, and optimizing simulation accuracy with non-steady-state coupling models. The experimental and simulation results show that the thermal conductivity of the composite PCM is increased to above 1.8 W/mK, and the temperature uniformity error is controlled at ?1?. At an ambient temperature of ?10-45? and a charge and discharge rate of 1-3C, the maximum temperature of the bionic structure + composite PCM system (experimental group B) is 8.6? lower than that of the control group, the equilibrium time is shortened by 29% during 3C discharge, the phase change latent heat retention rate reaches 91% after 2000 cycles, and the simulation accuracy exceeds 95%. This solution offers practical technical support for the thermal management of high safety, long-life power batteries.