[305] Time series analysis of high energy density lithium-ion batteries for electric vehicles applications

The use of lithium-ion secondary batteries in electric vehicles has now become a key component of high-performance energy storage systems. There are various factors that contribute significantly to the reduction in battery performance and subsequent damage of battery cells. The factors associated with battery degradation as a result of the charge and discharge rate is not new and has been investigated widely by many researchers. The maximum amount of electrical charge that a battery can store and deliver normally decreases over time. This capacity fade phenomenon is a result of various degradation mechanisms within the battery. The degradation mechanisms are random in nature and, in this paper, the degradation mechanisms associated with changes in the electrical impedance, capacity and the lifecycle of the battery cells are explored. 18650 battery cells are tested for 23 cycles on a trickle charge and the designated samples from each battery is subjected to different set temperatures, ranging from 20°C to 55°C at a constant time per experiment. Statistical analysis of the data is conducted using a time series approach and a reliability model is proposed in an attempt to predict the degradation or failure and hence improve the battery performance.