Investigation of bio-inspired battery thermal management system coupled with hybrid cooling schemes for high C-rate discharge conditions

The battery thermal management system (BTMS) plays a critical role for boosting both the performance and longevity of lithium-ion batteries (LIBs) in electric vehicles. The power and safety optimization of light electric vehicles (LEVs) leads to restrictions on the weight and complexity of BTMS. Evaporative cooling has the natures of high-efficiency heat dissipation, low cost, and compactness. It could be a potential solution for BTMS in LEVs. However evaporative cooling still suffers from poor temperature uniformity (ΔT) and insufficient heat transfer in conventional fluid channels. In this study, a bio-inspired hybrid evaporative cooling-PCM (phase change material) BTMS is optimized by employing biomimicry on both structural and functional perspectives: structurally, a red blood cell-shaped channel is proposed to optimize heat transfer and flow field distribution.; functionally, the PCM layer is employed as fat layer to reduce ΔT while the evaporative layer is served as skin layer to improve heat dissipation. The performance of this hybrid BTMS under high discharge rates are compared and analyzed by conducting single-cell BTMS experiments and battery pack numerical simulation. The results show that under a 5 C discharging the hybrid system can maintain the maximum temperature (T max ) and ΔT at 38.38 °C and 3 °C, respectively. This indicates that the BTMS achieves adequate cooling effect under high ambient temperature, high humidity, and high discharge rate conditions. Moreover, the coefficient of performance (COP) reaches 124.24, which is about 70 times higher than that of the liquid cooling system in the past decade, highlighting the significant advantages of high heat dissipation efficiency and low energy consumption.