Experimental Assessment of the Effect of Reference Surface Temperature on Auxiliary Energy Consumption in a Thermoelectric-Based Battery Thermal Management System

Thermoelectric coolers (TECs) have attracted considerable attention for battery thermal management owing to their compact structure, precise temperature control capability, and ease of integration. However, the influence of reference surface temperature on the auxiliary energy consumption of TECs remains insufficiently studied, despite its direct impact on the overall energy efficiency of battery systems. This study experimentally investigates the influence of reference surface temperature on the auxiliary energy consumption of a selective thermoelectric battery thermal management system (BTMS) operating under a constant 7.5C discharge condition. The reference surface temperature was varied from 35 to 40 °C in 1 °C increments to evaluate its effect on TEC activation behavior, cooling energy demand, and battery thermal performance. All results were obtained using a single 20 Ah LiFePO₄ pouch cell under a constant 7.5C discharge rate, with average ambient and coolant temperatures of 27.5 °C. The results showed that increasing the reference temperature substantially reduced both the activation duration and the total energy consumption of the TEC modules, decreasing the TEC energy demand from 5.88 Wh at 35 °C to zero at 40 °C and the corresponding auxiliary energy consumption from 11.70% to 0% of the battery energy capacity. A key finding of this study is that increasing the reference temperature from 35 °C to 36 °C resulted in only a 0.68 °C increase in the maximum battery surface temperature, while reducing the TEC energy consumption by more than 50%, demonstrating that substantial energy savings can be achieved with only a minor compromise in thermal regulation. The results indicate that the reference surface temperature is a critical design parameter governing the energy efficiency of thermoelectric BTMSs. The proposed experimental methodology provides practical guidance for selecting appropriate control thresholds that balance thermal regulation effectiveness, auxiliary energy consumption, and battery safety.