Combustibility and hazard of lithium iron phosphate power battery components in different aging states

In this paper, four kinds of aging states, capacity retention ratio (CRR) of 100%, 85%, 75% and 65% lithium ion phosphate power battery were selected as the research objects. The combustibility and smoke generation of key components of the battery (positive, negative and separator, all containing electrolyte) were studied by cone calorimeter. The fire risk assessment index system of batteries with different aging states was established by using AHP (analytic hierarchy process). The results show that the effective combustion heat value of the negative electrode decreases as the battery CRR declines, And the yield of CO₂ and total smoke production of battery components gradually decrease. The normalized risk index of battery components with a capacity retention rate of 100%~85% is significantly higher than that of battery components with a capacity retention rate of 75%~65%.