Development of an Equivalent Circuit for Batteries Based on a Distributed Impedance Network

Abstract

This paper presents an original equivalent battery model based on a distributed RC circuit. The model virtually includes an infinite number of time constants to reflect the battery behavior, especially during the dynamic stress test. The model has much fewer parameters than the traditional battery model and so reduces the parameterization effort significantly. The self-discharge is inherently implemented in the model as well. The second order partial differential equation of the model is derived and both explicit and numerical solution approaches are introduced to incorporate the model in any simulation environment or analytical response analysis. Incorporating the effect of the state of charge on the parameters of this model is more easily accomplished by changing the trends of the parameters as opposed to each of them individually. The model matches to various battery type and it is validated on a 30 Ah Lithium-Ion battery from 1 C to 8 C discharge pulse current. Furthermore, the results are compared to the classic battery model.