A fault-tolerant control architecture for different battery topologies in electric vehicles

In this paper a variety of battery conguration topologies for electrical vehicles (EV)are investigated w.r.t. reliability and expected lifetime along with the possibility of applying active fault detection to provide early warnings for the driver. Dierent congurations are investigated ranging from a simple single serial string of battery cells providing only the lowest level of fault tolerance, at the one end, to a highly elaborate and still practically relevant triple string conguration providing fault detection and recon guration possibilities as well as repair. All congurations are analyzed w.r.t. the associated reliability prole assuming an non ageing cell failure model. A novel method for active early fault detection is presented based on encoding faults into a parametric dynamic cell model, where parameters are continuously estimated under the influence of an auxiliary test signal designed to optimize parametric sensitivity. Finally reliability pro les for all investigated congurations are compared mutually and with standard requirements on the basis of mean time to failure (MTTF) statistics.