Investigation of Battery Heat Generation and Key Performance Indicator Efficiency using Isothermal Calorimeter

In this experiment-based research, the performance and behaviour of a pouch type Li-ion battery cell are reported. The commercial test cell has a Lithium Titanate Oxide (LTO) based anode with 13Ah capacity. It is accomplished by measuring the evolution of surface temperature distribution, and the heat flux of the battery cell at the same time. Temperatures on the surface of the cell are measured using contact thermocouples, whereas, the heat flux is measured simultaneously by the isothermal calorimeter. This heat flux measurement is used for determining the heat generation inside the cell. Consequently, using the heat generation result the important performance constituent of the battery cell efficiency is calculated. Those are accomplished at different temperature levels (-5 degrees C, 10 degrees C, 25 degrees C and 40 degrees C) of continuous charge and discharge constant current rate (1C, 2C, 4C, 8C, 10C (maximum)). There is a significant change in heat generation in both charge and discharge events on different temperature and C-rate. The heat flux change level is nonlinear. This nonlinear heat flux is responsible for the nonlinear change of efficiency in different C-rate in a particular temperature. The presented experimental technique is a very precise determination to profile the battery cell. The result of the research can be incorporated in constructing a precise datasheet for a battery cell which can assist the researchers, engineers, and different stakeholders to enhance different aspects of battery research.