Numerical investigation of nanofluid flow in thermal management of lithium batteries in vertical elliptical chambers filled with phase change materials

The present study numerically studies a rectangular battery pack (BTP) with three rows and seven columns of cylindrical lithium-ion batteries placed in an elliptical enclosure filled with PCM. The BTP with PCM-filled enclosures is located in a channel with a laminar flow of an eco-friendly nanofluid (NFD). Variables include the inlet and outlet dimensions in the range of 1–2 cm, the spacing between rows of batteries in the range of 0–0.3 cm, and the spacing between columns of batteries in the range of 0–0.4 cm. These variables are examined for 50 min. The simulation is conducted in COMSOL 6.0 software using the finite element method. Also, optimization is performed on the parameters using response surface methodology (RSM) to obtain the best conditions for the cooling system and BTP. Results showed that changing parameters can alter the NFD outlet temperature (TONF) by about 20.45 °C in the maximum and minimum conditions. The maximum pressure drop (PRD) occurs for the largest inlet dimensions, smallest outlet dimensions, and largest battery spacing, whereas the minimum PRD occurs in the conditions opposite to the former. The maximum pressure in the channel is 9.76 times the lowest PRD. The maximum heat transfer coefficient (HTC) in PCM is greater by about 131 % relative to its minimum value. Also, obtained results indicated that altering parameters and optimizing them, especially increasing the inlet channel dimensions, can increase the HTC in the NFD by 2.39 times.