Battery Management System Design For Fast Charging Electric Vehicles

With the energy depletion and environment deterioration, electric vehicles as anefficient, non-polluting means of transport, attracted widespread attention. Electricvehicle battery management system is, the heart of its safety and efficiency. Electricvehicle charging usually takes10hours, therefore, it is necessary to design electricvehicle charging takes longer, usually takes10hours, therefore, to design a fastcharging Battery Management System. Although Tesla’s management system tried toachieve “quick charging” by using multi-batteries, but this technology did not realizethe true fast charge. This paper is committed to design a safe and reliable fast chargebattery management system.Firstly, through the overall function analysis of battery management system, thecommon hardware modules of data collection and cell balancing are studied.Furthmore,the algorithms commonly used in battery and battery management toestimate, remaining battery power are analyzed in-depth. In this paper, a distributedsystem is designed according to the battery management system, the system isdivided into HCU (high voltage control unit), BMU (Battery Management Unit) andBCU (battery control unit). The control unit includes a high-voltage relay drivercircuit design, relay interlocking design, power control design and insulation testingwakeup design. Fast charging battery management system to achieve the samplingcell voltage, temperature detection, current detection accuracy and balanced solutionsput forward higher requirements.Aiming at these problems, the single cell voltagebalancing using sampling and special company Linear Battery Monitor LTC6803-2,the chip can simultaneously carry out12single battery voltage acquisition andbalanced.Temperature sensing, current sensing, CAN communication modulesprovides the hardware and software design.To further enhance the safety of thebattery management system, the paper adds collision detection design.Fast charge isachieved through the large current charging, the battery generally equivalent circuitmodel (eg Thermin model, Rint model) does not accurately reflect changes in realtime during the remaining battery charge and discharge electricity.In this paper, Professor Cecilio Balanco and Luciano Sanchez model based on lithium ironphosphate "bucket effect" proposed, given the parameters of the model test methodfor obtaining and using Matlab/Simulink to build a simulation model, the batterymanagement system PC platform designed and implemented in VB.This designed electric vehicle battery management system can real-timelyacquire, cell voltage, total voltage, total current, positive and negative insultationresistance, and accurately estimate the remaining battery SOC, realize fastcharging.The system performance test show that it maches the performancerequirements of electric vehicle battery management system.