Thermal management system for prismatic lithium-ion batteries coupling with U-type channels and pyrolytic graphite honeycomb fins

The battery thermal management system (BTMS) is crucial for the safety and lifespan of electric vehicles. This paper proposes a hybrid BTMS combining liquid cooling plates arranged on the side and pyrolytic graphite honeycomb fins (PGHF). The cold plate contains two U-type channels with staggered inlets, and the phase change material (PCM) is filled in the honeycomb fins. The internal resistance and entropic coefficient of the battery are obtained experimentally and used to model the battery's heat production. The heat dissipation capabilities of six different BTMS are compared at a discharge rate of 3C. Compared with traditional serpentine cold plate cooling, the designed BTMS reduces the maximum temperature, maximum temperature difference, and pressure drop by 5.32 K, 6.82 K, and 462.94 Pa, respectively, indicating significant improvements in cooling performance and substantial reductions in system power consumption. In this paper, the effects of different inlet mass flow rates and honeycomb fin porosity on the heat dissipation of the system are investigated to determine their optimal values. Results indicate that when the mass flow rate is 1.0 g∙s⁻¹ and the honeycomb fin porosity is 45.68 %, the maximum temperature of the battery is 310.38 K, the maximum temperature difference is 1.82 K, and the pressure drop is 279.35 Pa, which represents the optimal cooling performance.