Single Battery Voltage Acquisition And Equalization Scheme In Electric Vehicle BMS

The energy crisis and environmental pollution have become a global significantchallenges, and they are also the important factors that restrict the development ofthe global economy. The development of the car caused the huge energy loss, Theexhaust automobile emissions is one of the main source of air pollution, and is alsothe important cause of the national large-scale haze weather. So the development ofthe pure electric vehicles is the preferred options to meet the "zero emissions" incurrent. However, vehicle power battery is not only the technology bottleneck torestrict the development of the scale for electric automobile, but also is the keyfactor for the high price of the electric vehicle. With the development of the batterymanagement system of high performance, we can use the battery power moreeffectively and extend the battery life as well.The pure electric vehicle power battery consists of hundreds of single battery.When the battery used in groups, it is prone to charge or discharge, which causesthe loss of the battery capacity and the service life. There is a certain relationshipbetween the state of the battery charged (SOC) and voltage, we can estimate thestate of the charged battery by monitoring the single battery voltage. Duringcharging or discharging the Battery, the battery voltage and the temperature in thebattery pack must be monitored, so we can implement the corresponding controlstrategy according to the data collected, and maintain the consistency of the wholebattery voltage.This paper have made in-depth analysis and design of the the core issues such asthe single battery voltage, the temperature acquisition and the equalization controlstrategy. With the analysis of the advantages and disadvantages of the existingcollection and equalization scheme, this paper designed a set of solution for thesingle battery voltage detection and equalization, which can realize the function ofautomatic detection and equalization for the battery voltage, and keep thetemperature inside the battery pack in a reasonable range as well. The system usedthe CPU of FreeScale company as the main controller, and hardware circuit design,PCB drawing were successively completed. The underlying software driver wascompleted in CodeWarrier development environment using C language. Finallythe Monitoring and control board(voltage, temperature acquisition and control circuit board) was debugged, and we can intuitively monitor the data systemreceived and troubleshooting information through constructing system test platform,and verify the reliability of the whole system.