Research on parallel characteristics of lithium iron phosphate batteries for dual electric multiple units

Abstract

The performance of power lithium ion battery pack in parallel will be further degraded due to the inconsistency of the cells. Under different working conditions, battery pack in parallel reflects different charging and discharging characteristics. In this paper, based on the series-parallel simulation platform, the actual current of parallel battery pack was obtained from the power characteristic of dual electric multiple unit (DEMU). The charging and discharging characteristics of parallel connection for Lithium iron phosphate (LiFePO4) battery batteries with constant current and the loop current phenomenon under different state of charge (SOC) were investigated combined with the practical charging and discharging tests in the laboratory, which are helpful to get the main causes of aging of battery pack in parallel. An optimized usage range of SOC is proposed which provides the basis for battery management and prolongs the battery life cycle. © 2014 Springer-Verlag Berlin Heidelberg.