Steady state analytical model of a “time shared li-ion cell blancing circuit” for Plug-in hybrid vehicles and utility energy storage

Abstract

A steady-state analytical model of the recently proposed "Time shared li-ion cell balancing circuit" is presented in this paper. This paper provides the necessary analytical proof of the cell balancer circuit to be used in future Plug-in Hybrid vehicles (PHEV) or utility energy storage applications. The model presented here bridges the simulation and experimental results obtained previously. In addition, the prototype of a four-cell lithium-ion battery balancer circuit with reduced component count has been constructed, and the test results have been verified with the analytical model. Although the "proof of concept" circuit was built to balance only four cells, the analytical model suggests that any number of series connected cells could be used in a string and balanced. Moreover, the analytical model can be extended to characterize the circuit parameters for any number of cells without any apparent issues. This model was also being verified using the simulation and experimental results with only 2% error margin.