Cooling hybrid/electric vehicle battery module: exploring the thermal potential of single evaporator Loop heat Pipe

Abstract

ABSTRACTA novel Loop Heat Pipe (LHP) is developed as passive cooling system for Battery Thermal Management System (BTMS). LHPs are more efficient than traditional heat pipes at transferring heat at larger distances, which is essential for keeping the batteries in a safe and efficient temperature range. The Single Evaporator Loop Heat Pipe (SE-LHP) BTMS is tested on a battery module comprising of twelve 18,650 lithium-ion battery cells. The tests are conducted at various charge and discharge rates (1C, 1.5C, and 2C) and ambient temperatures ranging from 30°C to 45°C. The SE-LHP BTMS significantly reduces the maximum cell temperature compared to a module without BTMS. At an ambient temperature of 35°C, the SE-LHP BTMS attains temperature drops of 15%, 16.4%, and 16.29% during battery charge rates of 1C, 1.5C, and 2C, respectively. The SE-LHP BTMS also increases the discharge capacity of the battery module. For the 1.5C discharge rate, the discharge capacity increases from 41% State of Charge (SOC) to 0% SOC with the SE-LHP BTMS, compared to 39% SOC without BTMS. For the 2C discharge rate, the discharge capacity increases from 59% SOC to 0% SOC with the SE-LHP BTMS, compared to 56% SOC without BTMS. The SE-LHP BTMS also helps to keep even temperature spreading among the battery cells. When the module is exposed to ambient temperatures ranging from 30°C to 45°C, the SE-LHP BTMS keeps a temperature difference of less than 2.43°C and 3.38°C among the battery cells for all charge and discharge rates, respectively.