Power Battery Modeling Based on the Characteristic Field Theory

It is well known that battery is a key technology during the development of electric vehicle. To understand the battery's performance based on the vehicle's requirement is very important and necessary. In this paper, firstly, the definition of SOE (State of Energy) was put forward to reflect the combined fluctuation of battery's terminal voltage and current. Secondly, the basic principle of characteristic field theory is introduced, especially, the working characteristic field of battery is defined, that is, discharging energy field, working voltage field, open-circuit voltage field and internal resistance field. Based on experimental data and the characteristic field built, the battery model is made. Finally, through the simulation experiment of BJD6100-EV (a pure electric transit bus), the battery model's reasonability and exactness is verified, also, the reasonability of using SOE to evaluate the battery's state is shown through comparing with SOC. As a conclusion, using SOE to evaluate the battery's state is better than using SOC, and modeling battery based on the characteristic field theory is more useful for the evaluation of electric vehicle's performance than other complicated battery model.