Experimental Characterization of Battery Performance under Non-Uniform Temperature Gradient

Abstract

In order to ensure optimal performance of the batteries, a thermal management system (TMS) is suited in electric vehicles for the temperature control. However, due to the non-uniform heat generation of the large format pouch type lithium-ion batteries and the limitation of temperature control of the TMS, temperature gradient conditions are inevitable. Thus, the characterization of battery performance under temperature gradient is vital in scope of the current battery utilization system.

In this work, a high-performance multifunctional calorimeter was utilized to further analyze the behavior of the large format pouch type lithium-ion batteries under three segmented variant temperature applications in the longitudinal direction. For the quantification of heat generation, changes in cell surface temperature could be captured. The heat flux sensors were embedded to the system while the sensors were actively calibrated with thermal resistance heaters. The effect of temperature gradient on battery’s electrochemical characteristics could also be accurately attained through the capacity checkpoint measurements, and the heat generation characterization was performed at the beginning of life and while aging up to certain capacity marks. This effort enables a comprehensive understanding of the electrochemical, thermal, and degradation characteristics of batteries under temperature gradient load, which provides fundamental guidelines along with multi-aspect experimental data resources to increase lifespan, secure safe, and reliable operations for the battery system in the electric vehicles.