Study On Voltage Equalization Management System Of Series-connected Battery Pack For Electric Vehicle

In recent years, with the advantage of clean, energy-saving and environmentallyfriendly, electric vehicle has become the hotspot of the national research under theincreasing pressure of energy and environmental pollution. Power battery is the mainenergy source of electric vehicle. But less energy storage and limited service life of thepower battery has become the key problems, which restrict the development of the electriccar. Usually, single battery has to be used in series and parallel due to the defects of lowcapacity and low voltage. But as the difference in performance between the monomer,battery pack may appear imbalance problems between single batteries. This will influencethe efficiency of the battery and reduce the service life of the battery. So, solving theequilibrium problem of battery pack is of great importance for the development of electricvehicles.Starting from the previous topic, it analysis the advantages and disadvantages ofvarious equilibrium methods, and improve on it in this paper. Finally, this paper presentsan improved switch matrix balancing methods, and gives the corresponding topology.With this method, the number of switches is reduced by half. Meanwhile, the cost andcomplexity of hardware design is also greatly reduced.It considers the lithium iron phosphate power battery as the research object in thissubject. Hardware system has been designed based on the topology of the given earlier.Also, it designs the corresponding software system by combining the methods of deviationcontrol and periodic lag-compensation control, and completes the construction of thebalance management system test platform. At the same time, to facilitate the systemdebugging, this paper also designs a data input/output system and the upper machine testsystem. In addition, in order to improve system security, it joined the error alarm systemand emergency protective measures, basically perfected the battery equalizationmanagement system.Then, in the experimental platform, some discharge tests on lithium iron phosphatepower battery have been done. And data detected is received by the host computer system. Finally, this paper processes and analyzes the detected experimental data by the MATLABsoftware, and draws the test curve of the corresponding. The test results show that, thesystem can realize the management function of battery equalization. Thus, it verifies thefeasibility of the improved method.