The Method Of The Equalization System Of Electric Vehicle Power Battery

With the continuous development of economy, the impact of oil resources’shortage on the auto industry is unavoidable. At the same time, the environmental pollution which traditional fuel vehicles produce, has been a great influence on people’s lives. In such a situation, new energy vehicles come into people’s horizons. Pure electric vehicles are most remarkable in all new energy vehicles. At present, limited to the manufacture of power battery level, power battery which can satisfy requirements of vehicles’ drive power, is generally battery pack that composed by more monomer batteries in the form of series and parallel connection. The energy is inconsistent when single cells are used together, all that led to the decrease of the cell efficiency and shorten the life. In order to improve this problem, the balance of battery pack’s energy is of great significance.At first, this thesis analyses the root cause of battery pack energy’s inconsistency, then classifies the existing equalization technique, lastly introduces several typical methods in both passive equilibrium and active equilibrium direction. To judge the consistency of the battery power based on the parameters. Two methods of SOC and voltage are presented, and their advantages and disadvantages are elaborated respectively, finally the reason for choosing the voltage as control target is discussed.This thesis designs software and hardware of equilibrium system.As for software, topological structure of balanced circuit and the corresponding control strategy are designed. That’s proven feasibility by calculating and analyzing the energy conversion of equilibrium process.In hardware, the hardware circuit of system is divided into master, energy acquisition and processing module. Working principle and specific function of each module are analyzed. Besides, the selection of important components is elaborated. Finally, Along with the construction of the experimental platform, A series of discharge experiments are conducted with 12 single cells in equilibrium system and disequilibrium system. By comparing the experimental results, the equilibrium system in this thesis can achieve the expected effect in improving the energy balance of battery pack.