Analysis of Location-Dependent Temperature Characteristics of an ESS Battery Cell under Different C-rates and Cooling Conditions

The increasing use of energy storage systems has intensified the need for effective battery thermal management. This study investigated the location-dependent temperature characteristics of an ESS battery cell under different C-rates and cooling conditions. A 94 Ah prismatic lithium-ion cell obtained from a ESS module was instrumented with eleven thermocouples on its surfaces, terminals, vent hole, and side faces. Cooling conditions were defined as operation with and without heating, ventilation, and air conditioning (HVAC), and charge-discharge tests were conducted at 0.3C, 0.5C, and 1.0C. Without HVAC, the maximum temperatures were 29.9°C, 32.6°C, and 42.0°C, and the corresponding differences between the maximum cell and ambient temperatures were 7.3°C, 9.4°C, and 18.4°C, respectively. With HVAC, these values decreased to 29.2°C, 28.7°C, and 31.7°C and to 3.0°C, 2.4°C, and 5.4°C, respectively. Without HVAC, the hotspot was consistently observed at the negative terminal. With HVAC, it remained at the negative terminal at 0.3C but shifted to the lower front surface at 0.5C and 1.0C. Under the tested conditions, HVAC operation suppressed temperature rise and altered the spatial temperature distribution, providing useful data for temperature-sensor placement and thermal management design in ESS battery modules.