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A 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. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate the feasibility of a novel dual-evaporator loop heat pipe (DE-LHP) in battery thermal management systems (BTMS). A 3S4P (3-series and 4-parallel) Li-ion battery module with a 12.6 V and 10 Ah capacity is made and tested under various C rates for different environmental conditions. The battery generates an average heat of 11.28 W@1C and 24.44 W@1.5C with 100% discharge and 43.36 W@2C with 50% discharge at an ambient temperature of 30 °C. An increase in temperature from 30 to 40 °C results in a decline in the depth of discharge. The proposed DE-LHP is evaluated using deionized water with filling volumes of 12, 16, 20, and 24 mL. The DE-LHP started working above 5 W regardless of the filling volume, and before the evaporator reached dry-out, the DE-LHP transferred heat loads of 10, 30, 35, and 55 W with filling volumes of 12, 16, 20, and 24 mL, respectively. At a heat load of 30 W, the evaporator section of the 20-mL filled LHP demonstrated a minimum thermal resistance of 0.274 KW-1, while the condenser section exhibited a minimum thermal resistance of 0.372 KW-1 at a heat load of 35 W. The DE-LHP is found to be effective in transferring heat of 35 W to keep the module temperature below 60 °C. Based on these initial findings, it is suggested that incorporating the multi-evaporator LHP-based BTMS could be a feasible and efficient solution for the thermal management of battery modules/packs for electric vehicles. [ABSTRACT FROM AUTHOR]