Objective To enhance the heat dissipation capability of lithium batteries under high ambient temperature and high-rate discharge conditions, and to explore the synergistic working mechanism of thermoelectric cooling (TEC) and liquid cooling, a TEC-liquid cooling hybrid thermal management system is designed.

Method Targeting a specific 28-cell lithium-ion battery pack, a full-scale three-dimensional fluid-solid-thermal coupling model encompassing the battery pack, TEC assembly, and liquid cooling cold plate was established. Numerical simulation research was conducted using Fluent software.

Result The results indicated that the simplified TEC model and the multi-physics coupling simulation methodology can effectively simulate the heat transfer process of the TEC-liquid hybrid thermal management system. Under the operating conditions of a 1C discharge rate, a coolant inlet temperature of 50 ℃, and a TEC current of 10 A, the maximum temperature of the battery pack was controlled around 35 ℃. And a localized cold source was formed at the bottom of each cell. An increase in the coolant inlet temperature led to a rise in the average battery pack temperature and a slight decrease in the COP of the TEC assembly. A lower coolant inlet temperature was more favorable for the cooling performance of the TEC assembly; There existed an optimal range for the TEC operating current, both excessively low and high currents were detrimental to temperature control and energy efficiency.

Conclusion The proposed simulation model and methodology can effectively reflect the temperature distribution and comprehensive performance of the TEC-liquid hybrid thermal management system. The simulation results provide a theoretical basis and data support for the design and optimization of such systems.