Design and Characterisation of a Fuel Cell-Battery Powered Hybrid System for Vehicle Applications

A system design analysis for a hybrid power system intended for vehicular traction applications has been performed. The hybrid consists of an intermediate temperature solid oxide fuel cell (IT-SOFC) operating at 500-800degC and a sodium-nickel chloride (ZEBRA) battery operating at 300degC. Such a hybrid system has the benefits of extended range and fuel flexibility (due to the IT-SOFC), high power output and rapid response time (due to the battery). The high temperature nature of the battery and fuel cell also offers the potential for thermal integration between the two systems with associated efficiency enhancement. The methodology for sizing of the battery and fuel cell is explained and a combined battery/fuel cell model is used to assess the performance, range and fuel economy of the hybrid. The 'bench top' system being used to demonstrate the hybrid is described