Study On Battery Consistency Evaluation Method And Equilibrium Strategy Of Zinc Nickel Liquid

With the increase of the number of the pure electric vehicles,the pure electric vehicles have become the main tendency of the future development. The battery is a storage element and also the energy supplier for the pure electric vehicle.The superiority of the performance,the constancy of the available capacity and prolong life-span become the base of the PEV’s progress.To enhance the available capacity of the battery,make prolong the life time and insure the security in use,we need to manage and control the battery reasonably. So the battery management system and the battery equilibrium play a vital role on the pure electric vehicles.In this paper, we mainly study on the consistency and equilibrium strategies of battery,then design experiments.Through the experimental data we obtain the battery consistency evaluation methods. In order to improve the consistency of the battery, the paper propose battery voltage equalization method and capacity balance method. Finally, it realizes the goals that the consistency of battery evaluation and the battery pack equalization. The main works are as follows:Through the experimental research and environmental test on the problem of the battery’s inconsistency, this paper analyzes the effect of the battery’s inconsistency to the battery pack in use.This paper studies on the battery consistency in the terms of capacity,SOC,DC resistance and the self discharge, and does the curve graphs about battery DC resistance to SOC,open circuit voltage to SOC,efficiency to SOC,then analyzes the inconsistency of the battery.After the analysis of two、three、four and N batteries in series and the categories of the equilibrium. This paper discusses the equilibrium strategies based on external voltage and the balance strategies based on the capacity.The balance module hardware design:this paper chooses the the 16 bit MC9S12XEG128 as the main board MCU and 8 bit MC9S08DZ60 as the slave plate MCU. The design includes control module,voltage sampling module,current sampling module,temperature sampling module,equalization module,data storage module and CAN communication module.Drawing PCB board、welding and debugging. Software part:The battery management system is written and debugged in the environment of Code Warrior IDE. The combination of hardware and software is used in acquisitions of the voltage,current and temperature,the data are transferred to the monitor through the CAN bus,and the monitor can display the collected data in real time.The overall debugging part:The accuracy about the sampling voltage,the sampling current and the calculation of the SOC.