Research On Equalized Controlling About Lead-acid Battery

The batteries of Hybrid Electrical Vehicle (HEV) are connected in series to provide a high terminal voltage. The difference of initial capacity, voltage, resistance and temperature of each battery results in some cell overcharged or over-discharged in use. Because the capacity of some battery is lower than that of others, its capacity is completely consumed in advance during the discharge. Then,it becomes a consumer in the circuit, and others provide the energy to it. As a result, whole batteries are not in duty normally, and their service life shortens. During the charging, the battery whose capacity is firstly consumed up is early charged, and others cannot be fully charged. In fact the efficient capacity of whole batteries depends on the least capacity of one battery.Therefore, the inconsistent of characters parameters of the batteries for HEV severely decreases the performance of the vehicle. It is very necessary to equalize the batteries. Theoretical analysis and simulation on the equalization control of the batteries. This paper reviews the disadvantages of previous schemes of equalizing battery stack then presents a new technique which is simple but has high efficiency and reliability. The proposed scheme maintains diverter modules which can divert energy from powerful batteries to weak ones automatically in non-dissipative manner. It can prevent batteries from overcharge by ensuring the whole battery stack at an equalized charge level at later charge/discharge period, so the battery life is enhanced. The simulative results prove the correctness of the analysis. They are completed in this dissertation:â‘ On the basis of characteristic on the charge/discharge of the battery, the dynamical model of the charge and the discharge is established.â‘¡The inconsistent of performance parameters of Lead-acid battery for HEV and the infective factors are analyzed. Then, contrast and analyze the ecologies in existence.â‘¢On the basis of dynamical and statistical model acquired,equalization control strategy on the charge/discharge processing is setup and the simulation on equalization control of charge/discharge are done.