Modeling of capacity attenuation of large capacity lithium iron phosphate batteries

As the market demand for energy storage systems grows, large-capacity lithium iron phosphate (LFP) energy storage batteries are gaining popularity in electrochemical energy storage applications. Studying the capacity attenuation rules of these batteries under different conditions is crucial. This study establishes a one-dimensional lumped parameter model of a single lithium-ion battery to obtain its electrical characteristics. Simulation results demonstrate that the lumped parameter model can accurately simulate battery characteristics while disregarding factors like battery material and size, striking a balance between speed and accuracy. Based on this model, a semi-empirical and semi-physical capacity decay model, considering calendar life and cycle life, is developed. Key aging parameters necessary for the model are fitted based on a small amount of measured lithium-ion battery aging data, enabling the prediction of aging patterns of LFP batteries.