Software Design Of Phosphoric Acid Iron Battery Management System

With the development of electronic technology, the requirement for large-capacityand long life lithium battery is higher and higher, which used for not only phones,notebooks, cameras and other small devices, but also electric cars, airplanes and otherlarge devices. Rechargeable batteries develop from lead-acid batteries to nickelcadmium nickel-metal hydride batteries. Lithium batteries come out and commercialproduction come into being until1991. Because of the advantages of large capacity,high voltage, recyclability and other advantages, lithium batteries had been the mostpromising batteries compared with other batteries and are developing continuously.However, due to its inherent characteristics, production technology and other issues,lithium batteries also have disadvantages of self-discharge, charge anddischargeunevenly, security risks and so on. Based on research of these problems, thisarticle designsinformation collection, controlling and storage of battery managementsystem(BMS) to overcome the disadvantages, give full play to the advantages of battery.In this paper, the microcontroller of BMS is MC9S12XS128. Through thetemperature acquisition, voltage acquisition, current acquisition and insulation detectionto obtain all kinds of information of battery pack, system estimates state ofcharge(SOC), balances inconsistent battery, alarms even cut off when batteries are indanger. This paper mainly contains the following aspects:First, the paper describes the research status of lithium BMS, analyzes the lithiumiron phosphate how to work. On this basis and combining with the practical requirementofBMS project, paper proposes overall design.Then, the paper focuses on the running processesof microcontroller software andPC software in detail. PC softwaredesigns interface through MFC programming,communicates with BMS though CAN interface card driver program. LPC programsand debugs through CodeWarrior,calculates battery temperature by dichotomy andlinear interpolation, collects battery voltage by simulating SPI timing, calculates thecharge and discharge current by the Hall sensor’s approximately linearrelationship andoffset correction,calculates SOC by Ah integration method and SOC-Vol table.Atlast,based on all kinds of information,system determines the state of battery and thentakes action such as balancing, alarmsor disconnectsto efficientlymanagethe batterypack. Finally, the paper analyzes and verifies the requirements of BMS. Results showthat not only the system is able to manage battery pack efficiently, but also the BMS hasa great promotional value and broad market prospects due to adjustable parameters andhardware and software can be upgraded.