Study on preheating and temperature maintenance performance of an integrated thermal management system during charging

In low-temperature environments, incomplete internal reactions during charging and discharging can degrade battery capacity and reduce efficiency. To address this, the study explores the use of electric heating films for preheating and thermal insulation in a battery thermal management system, integrated with phase-change liquid cooling for temperature control and thermal runaway suppression. First, the impact of heat flux density and heating surface layouts on heating efficiency was analyzed with the liquid cooling system deactivated. The results show that heat flux density significantly affects temperature differences during preheating. Simultaneously heating the minor side and bottom surfaces improves preheating efficiency, and heating both the battery and battery thermal management system together reduces the temperature difference. With a heating power of 2000 [Wm-2], the battery reached 25°C from an initial temperature of 0°C in 1769 seconds. In the 1 C charging and thermal maintenance phase, activating the liquid cooling system and setting the heating power to 200 [Wm-2] kept the minimum battery temperature around 27°C, with a temperature difference of 2.6°C.