An experimental study on the cooling performance of capillary driven evaporative cooling for cylindrical cells

Capillary driven evaporative cooling (CDEC) is a novel concept that can directly wet-cool the surface of the battery through evaporative cooling. In this study an experimental setup was developed to establish the applicability of CDEC in cylindrical cells and to test its cooling performance compared to other battery thermal management systems. The test rig was designed using emulated cylindrical cells to test the performance of the cooling system using SF33 and Novec 7000 as working fluids. Results revealed that both working fluids were capable of maintaining the cell temperature within acceptable temperature limits. For a constant heat load of 10 W per cell (531 kW/m3) it was found that the cell average temperature can be maintained below 40 degrees C with both SF33 and Novec 7000. Furthermore, it was found that CDEC can ideally maintain the temperature uniformity within 5 degrees C along a cell and between the cells in a module. SF33 with its low specific heat capacity and low saturation temperature shows a faster response and high cooling rate compared to Novec 7000. Furthermore, it was shown that the overall thermal resistance of the CDEC system was as low as 1.5 K/W. It can be concluded that SF33 and Novec 7000 are promising working fluids for capillary driven evaporative cooling battery thermal management systems even though SF33 would be a better alternative to Novec 7000.