Research And Development Of Large Capacity Lithium Battery Management System

Large capacity lithium battery is gradually replacing lead-acid battery,and become communication base station battery back-up power and other energy storage equipment,which is widely used.Lithium-ion battery pack need to be equipped with complete lithium battery management system.Li-ion battery management system is unsuitabe,suitable for low voltage of the battery pack.In order to solve the above problems,this paper developed a new type of high-capacity lithium battery management system.The system is mainly used to achieve the lithium battery within the monomer overcharge,over discharge,over current,high temperature protection protection control.Buzzer and remote communication system for display and operation.In this paper,the BMS is composed of hardware and software.The hardware of the BMS includes power supply module,analog acquisition module,voltage balancing module,power protection module and communication alarm module.AFE has two MCU each carking an analog front-end chip,to realize the monomer voltage detection,charge and discharge current detection,temperature detection,and other functions.Using a 32 bit MCU as the master control chip,and realize the remote communication,charge state estimation and fault alarm,charge and discharge protection,system upgrades,and core functions.In addition,the system use an external microcontroller as external watchdog to guarantee the system running in a stable way.The software of the BMS,li-ion battery management system includes on-chip communication,transformation of digital conversion,state machine,estimation charged state,charge and discharge management and remote communication and several big function modules.The on-chip communication module and the transformation of analog to digital conversion module are used for collecting the front-end analog quantities such as voltage,current,temperature,the maximum temperature compensation and software calibration algorithm,are used to improve the precision of sampling;State of desktop module is realization of lithium battery protection logic part of the action,according to the amount of input/output system,to sign an assignment;Charged state estimation module is using Ann integral method and the open circuit voltage method of software algorithm to implement the accurate estimation of SOC;Writing remote monitoring subroutine according to the standard communication protol miit.remote monitoring and the with a friendly man-machine interface with PC software of parameter Settings.Finally,the design and development of large capacity lithium battery management system are analyzed in a series of tests,and obtain the relevant experimental data.According to the result of the experiment on the system voltage,current,temperature sampling precision calibration,the charge and discharge protection,balance control is verified and improved.Finally verified in this paper,the design of the large capacity lithium battery management system is in accordance with design requirements.In the last part of paper,the design of lithium battery management system are summarized and prospected,and sum up in current job defects and the direction of next stage.