Study On Battery Management System Of Lithium-ion Batteries

With the modularization of the large-sized Li-ion batteries and the widely used of the middle-sized batteries, the cycle life and safety capability of Li-ion batteries have become the primary problems to hinder development. Currently the battery management system (BMS) was focused in the study for its mitigating the adverse effect of these problems.The BMS, including the electric quantity gauge system, the status management system and the balance control system, was studied in this paper, and the safety capability of the Li-ion batteries was improved and the cycle life of the Li-ion batteries was prolonged.The investigation on the accuracy of current sample and the gauge arithmetic indicated that the gauge accuracy especially at the end of the cycle life was kept within 5% by the adaptive modification of the cycle life.The research of low power dissipation of the BMS showed that the power dissipation was around 200mW by circuit optimization such as single-power-supply. The cycle life was gauged accurately by the arithmetic, the electric quantity gauge system and the balance control system was adaptive modification of the cycle life, each module of BMS was organically combinated.The study of the consistency of the batteries revealed that the effect of voltage measurement circuit on the consistency of the Li-ion batteries was obvious, and a novel voltage measurement circuit was designed to decrease the adverse effect. The investigation on the factors which caused the Li-ion batteries to deteriorate acutely demonstrated that overcharge, over-discharge, temperature difference and charge ratio difference were the most reasons which caused the battery worsened. The cycle capability of the Li-ion batteries was studied, and the experiment indicated that the cycle life of filtered batteries with protection was only around 220, while the cycle life of the unfiltered batteries with BMS of novel control strategy which mitigated the acute deterioration of the worst battery was above 1000. The reliability and the anti-jamming of the BMS was studied, the reliability of the system was improved by the optimization of the hardware and software design.