Abstract

Temperature is known to greatly affect the efficiency, security, and cycle life of lithium-ion battery (LiB) cells. LiB cells are delicate to changes in temperature by using a variety of nanofluids. This study uses a novel cooling system with a Re between 15 × ۱۰۳ and 30 × ۱۰۳ to lower the cells’ temperature. Al2O3, CuO, SiO2, and ZnO with nanoparticles concentrations of 5% and nanoparticle diameters of 20 nm dispersed in a base liquid (water) are used to produce the effects. The findings demonstrate that as the Re rises, so does the Nusselt number. An innovative cooling system is designed and numerically tested to show how different kinds of nanofluids affect the increment in heat transmission and distribution of temperature in LiB cells. The temperature of LiB cells drops by flowing the water between the 52 batteries inside the cooling pack. For each spacing value, the Reynolds numbers are increased, which results in an increase in the average Nusselt numbers. According to the computational fluids dynamics results, the Nusselt number rises with increasing spacing. The results show that Re of 18000, 22000, 25000, 27500, and >30000 are needed for SiO2 nanofluids, Al2O3 nanofluids, ZnO nanofluids, CuO nanofluids, and pure water, respectively, to get battery pack temperature of <40 °C (the typical operating conditions). Higher Re values improve the heat transfer slightly with the expense of pumping power; therefore, Re of 18000 with SiO2 nanofluids is preferred. The utilization of nanofluids also shows that SiO2 exhibits the best thermal cooling for battery packs among all investigated nanofluids. Al2O3 nanofluid is also an excellent option, followed by ZnO nanofluid. For example, the temperature reduction of the hottest battery cell reaches >47, 44, 43, 42, and 42 °C for SiO2 nanofluids, Al2O3 nanofluids, ZnO nanofluids, CuO nanofluids, and pure water, respectively.

Introduction

The Greater demands for battery thermal management systems (BTMS) have been made as lithium-ion batteries are increasingly used in solar systems, power electric cars, and any engineering applications People are most concerned with the temperature at which batteries operate, their reliability, their safety, and their cycle life. The fluid cooling system can manage the peak battery temperature and the temperature differential among batteries within a tolerable range, therefore increasing the cycle battery’s lifespan [[1], [2], [3]]. However, the operating temperature has a significant effect on the efficiency and life of lithium-ion batteries. Too high or too low an operating temperature can damage the battery’s cycle life, efficiency, dependability, and safety, as well as cause substantial degradation of its charge and discharge performance [4,5]; Sheng, Su, Zhang, Li et al., 2019; Z [6]. When a lithium-ion battery’s working temperature is raised from 25 to 50° Celsius, the capacity loss increases by 100% after 300 cycles. Lithium-ion (Li-ion) batteries, as a vital element of electric automobiles (EVs), have drawn considerable interest in recent years [7]. Due to their high energy and power density, long cycle life, and low self-discharge, Li-ion batteries are considered the best energy storage technology for electric vehicles in comparison to other types of rechargeable batteries.

Conclusion

This paper investigates an effective cooling process for a battery pack having 52 batteries in a staggered arrangement (5 rows and 21 columns) using four nanofluids (i.e., SiO2, Al2O3, ZnO, CuO) and pure water. The flow and energy equation is modeled using ANSYS Fluent, which is validated against reported experimental data. The nanofluids are taken at the same concentration (5 vol%) and particle size (20 nm). Based on the applied conditions, the following remarks are concluded:

– Higher Re values result in a better cooling process and reduce battery cells’ temperature. To get a typical battery pack temperature of <40 °C, Re = 18000, 22000, 25000, and 27500 for SiO2, Al2O3, ZnO, and CuO nanofluids, respectively, should be used compared to Re > 30000 for pure water.

– The hottest battery cell temperature could be dropped by 47, 44, 43, 42, and 42 °C for SiO2, Al2O3, ZnO, CuO, and pure water, respectively.

– SiO2 is preferred since it cools all battery temperatures by < 40 °C with lower Re (i.e., 18000).