Study On Intelligent Management Of Lead-acid Battery For Bus

The use of new energy bus,such as hybrid vehicle and electric vehicle,has been vigorously promoted in the public transportation.It requirements battery system has safety protection,good performance and diverse functions.The battery system is responsible for power distribution,circuit protection and control.Also,it is the guarantee for the normal use of electric equipments and vehicle safety.The intelligent management of bus battery system will improve component performance,operating reliability and safety.Intelligent management system is used to monitor and manage working process of lead-acid batteries in the bus,include detecting real-time status parameters of battery,estimating state of charge(SoC)of battery,fault diagnosis and alarm,intelligent design of node,control according to overcharge and over discharge.First of all,on the basis research of domestic and foreign,technical improvements are made on the design and implementation of intelligent management system about lead-acid batteries in the bus,such as the introduction of controller area network(CAN)bus,SoC estimation method fuses methods and parameters,fault diagnosis model,bootloader and information calibration.Secondly,studied the factors which affect the state of charge of battery,analyzed the advantages and disadvantages of existing estimation methods.After that,it proposes a new method for estimating state of charge of lead-acid battery.The new method combines Ah-time,open-circuit voltage and Kalman filtering law.In order to improve accuracy,it takes into account the effects of battery charging efficiency,discharge efficiency,temperature and battery aging.The new method is divided into two parts:initial SoC estimation and running SoC estimation.Then,studied the controller area network(CAN)bus.Based on parameters of the running battery system and CAN communication protocol,design the node message matrix,realize sharing battery system information with other electric control unit(ECU).In order to facilitate commercialization and post-development,the functions of bootloader and information calibration are designed based on CAN bus,designed communication protocol,implementation flow and guarantee mechanism.Also,corresponding upper computer software,which has same communication protocol with ECU,is designed for them.At the end of the paper,the software and hardware of intelligent battery management are designed.The effectiveness and reliability of the designed scheme were verified in laboratory and bus.The tests were divided by function.Last but not least,it analyzes and summarizes the result of tests.