Advanced Thermal Management for Electric Vehicle Batteries Using High Thermal Capacity Slurry

Battery thermal management systems (BTMS) in electric vehicles directly impact the battery packs’ performance, size and lifetime. Cooling channel arrangement and adopted working fluid are two of the major characteristic features of BTMS. This study evaluates the cooling potential of microencapsulated phase change material (MPCM) slurry in BTMSs for three commercially used models under 3 C and 5 C discharge rates. The effects of MPCM slurry concentration and cooling channel designs on temperature distribution and pressure drop over mass flow rates are analyzed. The thermophysical properties of MPCM slurry, including thermal conductivity, latent heat, specific heat capacity, and viscosity, were experimentally measured and applied to the simulations. It is observed that MPCM slurry can enhance temperature uniformity and reduce the maximum temperature in BTMS, in a direct relationship with the mass concentration of particles and the mass flow rate of coolant. However, considering the exponential increase of pressure drop with MPCM concentration, an optimal BTMS design is needed based on application-specific constraints. In the design aspect, the continuous spiral channel (Design A) achieves 17% and 34% better cooling than two spirals (Design B) and parallel (Design C) channels, respectively, but incurs 52% and 89% higher pressure drops, underscoring the tradeoff between performance and hydraulic efficiency.