Various coolants exert different effects on the cooling performance of liquid cold plates employed for EV battery cells. This research investigates the influence of utilizing CuO/water nanofluid on the liquid cold plate�s thermal and hydraulic performance. The present study uses 40 nm CuO nanoparticles with a 1 volume fraction, and the CuO/water nanofluid is prepared using a two-step method. Using CuO/water nanofluid achieves a lower surface temperature than water at different Reynolds numbers, with a maximum difference of 4.2 at Reynolds number 382. At Reynolds number 1530, the nanofluid achieved a surface temperature of approximately 35°C, well within the recommended operational range for Li-ion batteries. The heat absorption capacity of the nanofluid was enhanced by 3.21 J/s between Reynolds numbers 574 and 765, attributed to its higher thermal conductivity and specific heat capacity. The Nusselt number for the nanofluid surpassed that of water beyond Reynolds number 1147, indicating superior performance facilitated by improved fluid mixing. The maximum increase in pumping power consumption was 25.2 at a Reynolds number of 956. However, this penalty is small compared to the energy saved due to the better cooling performance of CuO/water nanofluid. © 2024 Taylor & Francis Group, LLC.