Experimental investigation of direct contact baseplate cooling for electric vehicle power electronics

An experimental setup has been built to investigate the thermo-hydraulic performance of the direct contact baseplate cooling technique for power electronics in electric vehicles, to improve the design and to validate the modelling of this technique. The setup consists of an electrical heater to emulate the heat dissipation of the power electronics and which is cooled by a 60/40% mixture by mass of water-glycol. It is equipped with a flow rate sensor, absolute and differential pressure sensors and temperature measurements at the inlet, outlet and baseplate over the channel length, to determine the performance parameters used in the comparison: thermal resistance and pumping power. Three fluid inlet temperatures, four power levels and four flow rates have been tested for three channel heights (1.5mm, 3mm and 7.6mm). Increasing the fluid temperature and/or heating power, results in a lower thermal resistance and pumping power, due to a lower viscosity of the fluid. The performance of the 1.5mm and 7.6mm channel was found to be quite similar, while the 3mm channel results on average in a 5.8% lower thermal resistance compared to the other two channel heights. The heat transfer in terms of the Nusselt number was also evaluated in function of the Reynolds number. By analyzing the hydraulic and thermal entrance lengths it could be concluded that the flow in all measurements is simultaneously developing. A comparison with two correlations from scientific literature for simultaneously developing flow did not show a good agreement, possibly due to the specific inlet and outlet effect, which is more pronounced for a bigger channel height than a smaller channel height.

ISBN:9781728124612

Publication year:2019

BOF-keylabel:yes

IOF-keylabel:yes

Accessibility:Open