Cold plate enabling air and liquid cooling simultaneously: Experimental study for battery pack thermal management and electronic cooling

Abstract

The temperature of cells varies greatly during dis/charge while their performance and lifetime are greatly affected by this fluctuation. Elevated temperatures may yield battery fire due to thermal runaway as well they accelerate ageing and capacity fade of cells. Thermal management systems are a necessity for electric vehicles to extend the lifetime of battery cells and eliminate any fire risks, especially for fast dis/charging applications. Here, we document a hybrid cold plate with a working fluid(s) of sole air or liquid as well as both of them. Hybridization of air and liquid cooling promises to minimize energy consumption requirements during a charge/ discharge cycle by combining the benefits of both thermal management strategies if energy management is controlled accordingly. The temperature of each cell can be kept below 30 degrees C with the proposed hybrid cooling heat exchanger, and the temperature difference between the cells is reduced by 30 % relative to liquid cooling. The maximum temperatures are decreased by 18 % and 3 % in hybrid cooling when compared to air and water cooling, respectively. Furthermore, a step function combining various discharge rates (1C and 3C) was employed in experiments to mimic a realistic situation, i.e. variable C-rate rather than constant. The results show that the temperature of the battery cells can be kept below 30 degrees C with air cooling for variable discharge rate and the effect of contact resistance should not be overlooked for liquid cooling. Furthermore, the possible use of the proposed hybrid cold plates is surveyed in the cooling of electronic devices which produce more and continuous heat than cells. Therefore, three resistance heaters with a capacity of 50W are used in experiments as well. The results show that the proposed cold plates could be used in both electronics cooling and battery thermal management with a control algorithm to switch between sole working fluid and combination modes which could be developed based on the results of this paper.