The thermal and hydraulic performance of liquid cold plate with novel internal design for electric vehicle battery thermal management

Abstract

Around the world, there is a significant increase in the number of electric vehicles (EV) on the roads. Among the reasons are due to many countries’ aims to reduce the dependency on the oil as energy source and the environmental aspect, for example the global warming which affect the planet where the transportation represents 30% of it, where the EV is one of the solutions for the global warming. The battery is considered as the main source of power for electric vehicles, but the battery tends to generate significant amount of heat due to an internal resistance during the operation. The generated heat during the charging/discharging processes could lead to overheating in the battery which could end in battery failure. Therefore, dissipating the generated heat in the EV battery becomes essential through thermal management systems to ensure that the battery operates within safe temperature range. The aim of the present experimental study is to introduce a new design of liquid cooling system and to investigate the effective parameters which affect its heat transfer and hydraulic performance. For this purpose, a new liquid cold plate (LCP) with cylindrical fins has been designed and fabricated. There are three focus areas for the research; to study the effectiveness of the shower head in improving the working fluid distribution inside the LCP system and thus improve the heat transfer and temperature uniformity of the battery cells, the effect of using internal perforated LCP with cylindrical fins and the effect of using CUO/WATER NANOFLUID as working fluid in the LCP. All the studies are tested under Reynolds number range between 382 – 1530. To determine the impact of each part used in the present LCP, comparisons are made between the regular and the shower head design, between the internal perforated LCP with cylindrical fins and oblique fins, and between the performance of water and CUO/WATER NANOFLUID as working fluids. Finally, the Design of Experiment program is used for the optimization purpose. The results indicate that the shower head achieved reduction in the surface temperature of the battery cell with significant difference at the low Reynolds numbers. It provides good temperature uniformity compared to the regular inlet that is due to the ability of the shower head to achieve good distribution for the working fluid flowing inside the LCP. For the hydraulic performance, there is no significant difference between the two inlets. There is a clear difference in the surface temperature of the battery cell when using cylindrical and oblique fins. The same observation is found for the temperature uniformity because of its ability to cause better fluid mixing and bigger heat absorption through the working fluid. Hydraulic performance of the internal perforated LCP with cylindrical fins achieved better performance. The impact of using CUO/WATER NANOFLUID to create better battery cooling compared to using water is low, where the differences in the surface temperature of the battery cell is not big while it is almost the same for the temperature uniformity. The hydraulic performance using water gave slightly better performance compared to using the nanofluid. The features of the current novel LCP design are the capability to ensure that the battery cell operates under 41oC and having good temperature uniformity at Reynolds numbers 382-1530 without causing high pumping power consumption penalty.