Thermal performance of a hybrid cooling plate integrated with microchannels and PCM

The battery thermal management system (BTMS) is critical to electric vehicle (EV) safety and performance. In this paper, a novel cooling plate integrated with liquid microchannels and phase change material (PCM) is developed for use in BTMS, and its thermal performance at a high discharge rate of 5C is investigated. To improve temperature inhomogeneity, the non-metallic inlet shell is used to transport the coolant to the axial microchannels, which significantly reduces the temperature difference by 3.8 °C. Additionally, compared with I-shaped microchannels, the design of S-shaped microchannels increases the flow area for coolant and promotes the cooling effect, controlling the maximum temperature at 34.53 °C. Then, the parameters, including the number of microchannel layers, radial extension angle, inner diameter, and PCM thickness, are optimized by the multi-objective optimization, and its energy consumption is decreased to 9.61 × 10-6Wh and its energy density raised to 108.94 Wh∙kg−1. Moreover, the cooling performance improves with the increase of the inlet velocity, and a balance between cooling performance and energy consumption is achieved when the inlet velocity is 0.06 m∙s−1. Cross-convectional flow helps to enhance the temperature uniformity of the battery module further. The hybrid liquid cooling plate takes advantage of coupling active cooling and passive cooling; the energy consumption of BTMS is reduced by 46.3% without sacrificing the cooling capacity when delaying the beginning of active cooling after PCM passive cooling for 300 s. Furthermore, the PCM-embedded hybrid cooling plate slows the heat loss of batteries in cold environments, which can maintain their temperature above 20 °C after resting for 2 h at 0 °C. This work provides a reference for the hybrid cooling plate development of cylindrical batteries.