Study on the thermal behaviors of power lithium iron phosphate (LFP) aluminum-laminated battery with different tab configurations

The thermal response of the battery is one of the key factors affecting the performance and life span of lithium iron phosphate (LFP) batteries. A 3.2 V/10 Ah LFP aluminum-laminated batteries are chosen as the target of the present study. A three-dimensional thermal simulation model is established based on finite element theory and proceeding from the internal heat generation of the battery. The study illustrates a three-dimensional relationship among the total internal heat generation rate of the battery, the discharge rate of the battery, and the depth of discharge. The effects on the heat distribution of the battery cells by different types of tab distributions are also explored. Results show that the thermal behavior of the discharge process can be effectively simulated with the Bernardi equation, by coupling the dynamic changes of the battery temperature, internal resistance and voltage temperature coefficient. The interior chemical reversible heat of the battery is manifested by the endothermic process when DOD (Depth of Discharge) is smaller than 0.7 and by the exothermic process when DOD is larger than 0.7. The irreversible heat takes an increasingly dominant role with the increase of discharge rate; under the condition of high-rate discharge, batteries with a single-side tab distribution are generally found to have a non-uniform cell temperature distribution, while those with a double-side tab distribution have improved cell temperature distributions. Widening the tabs can also greatly reduce the maximum temperature of the cell.