Investigation on thermal performance of water-cooled Li-ion pouch cell and pack at high discharge rate with U-turn type microchannel cold plate

Abstract

The objective of this study involves investigation and simulation on thermal performance of water-cooled lithium-ion battery cell and pack used in electric vehicles at high discharge rate with a U-turn type microchannel cold plate and recommending an optimal cooling strategy by considering the effects of various parameters including different discharge rates, inlet coolant mass flow rates, inlet coolant temperatures, surface area coverage ratios via changing the number of cooling channels, channel hydraulic diameters via changing maximum width of cooling channels, and flow pattern layouts. Experiments were conducted and the simplified heat generation rate calculation method was proposed to use as input heat source in the numerical study. The cold plate with surface area coverage ratio = 0.750 and channel hydraulic diameter = 1.54 mm was suggested to enhance battery cooling. The suggested flow pattern layout corresponding to cross flow with alternate single inlet and single outlet channel decreases the maximum temperature and temperature difference by 32.2% and 950.1%, respectively, when compared to the original flow pattern layout corresponding to parallel flow with 10 inlet channels at one side. The study demonstrated that optimized cooling parameters could maintain the maximum temperature and temperature non-uniformity of 50 V battery pack below 40 °C and 4 °C, respectively.