Battery charging and discharging kit with DAQ to aid SOC estimation

The already existing energy problems in today's world are leading to the research and discovery in the area of energy management system. Hybrid electric vehicles (HEVs) are found to be the remarkable solutions for the worldwide environmental and energy problems caused by automobiles. Unlike fuel gauge in IC driven vehicles EVs do not have any direct method of measuring distance to charge. EVs, however makes use of state of charge (SOC). The problem is that SOC cannot be measured directly but requires model of the battery for estimation. The model of the battery can be developed by obtaining charge and discharging characteristics of the battery at various currents. The main objective of the paper is to present the experience of development of a battery testing kit consisting of a charger, a discharging network and data acquisition (DAQ) to capture the data onto a PC. The Simulink model of the battery test kit is presented along with the prototype been developed as the part of the project. At last for capturing and storing the battery characteristics, Data Acquisition System (DAQ) is developed using ARM7 processor. As the paper progresses further, the charging and discharging characteristics of battery at various constant current is shown through digital oscilloscope and lab view software tool.