Thermal‐Hydraulic Performance of Microchannel Heat Sink for Water‐Cooled Lithium‐Ion Batteries

ABSTRACT Electric vehicle lithium‐ion batteries generate high thermal loads that require compact, high‐efficiency liquid cooling. This work investigates microchannel heat sinks with elliptic reentrant cavities (ellipticity 0.4, 0.6, 0.8, and 1.0) for electric vehicle battery cooling. We integrate them into a full‐scale cold plate, couple a Bernardi heat‐generation model with conjugate heat‐transfer simulations, and validate experimentally. Results show surface temperature decreases along flow; ellipticity = 1.0 gives lowest and most uniform T. At 60 mL/min, raising ellipticity from 0.4 to 1.0 cuts pressure drop from 180.5 to 140.6 Pa and lowers peak T by ∼2.1 K. Vorticity ranks 1.0 > 0.8 > 0.6 > 0.4. Outlet coolant T peaks near 30 mL/min due to competing vortex mixing and thermal capacity. Ellipticity = 1.0 offers the best thermo‐hydraulic trade‐off, confirmed by performance evaluation criterion (PEC).