Passive thermal management of battery module using paraffin-filled tubes: An experimental investigation

The use of carbon tubes filled with paraffin as Phase Change Materials (PCM) in a battery module designed for Electric Vehicles (EV) is experimentally studied in this manuscript. Three different placements of such tubes in between twenty 18650 battery cells are proposed and evaluated based on the measured temperature profiles inside the module under discharge rates of 1, 2, and 4 C (50, 100, and 200 A, respectively). In general, all three configurations could have an average temperature of no more than 40 °C and 55 °C for 1 and 2 C, respectively. In contrast, the 4 C discharge test shows only two out of these three configurations could still maintain an acceptable temperature profile below 70 °C. The first configuration, which offers the most straightforward design among the three, would not withstand any constant discharge rates higher than 1 C. In such as case, it could be recommended to have a spread-out placement of the PCM tubes in the battery module as in the third configuration to prevent the accumulation of dissipated heat around the battery cells, despite a possibly more complex wiring system and installations. In terms of the degree of temperature uniformity, the minimum values of all three configurations lie within the range of 0.60–0.79.