Design Of A Batteries Equalization System

The present paper improves the existed method of equalization system for the implement of Li-ion batteries string equalization. A Batteries Equalization system referencing the voltages of batteries is realized and a monitor method of model parameter based on SOC is proposed.Firstly, the present paper introduces the technical background and study significance of batteries balance system and the status quo of the same. The develop process, the internal structure, operating principle, the parameter index evaluating features of the Li-ion, a method of charging and discharging and the circuit structure of batteries balance are discussed in the paper by a deeply study of Li-ion. Further, a balance circuit topology and a charging method are introduced.Then, the design steps of the hardware circuit is introduced here. A design index is determined referencing batteries parameter. The design of the balance module is accomplished, including the design of main circuit, modeling the balance circuit by using the method of small signal modeling according to Li-ion battery model, designing the compensation circuit, simulating the circuit compensated by using mathcad, accomplishing the controlling circuit according to a controlling chip and simulating the circuit by using saber. Further, a sensor module is designed according to the sensor chip chose here. And then, the significant hardware circuit of the circuit board of DSP TMS320LF2407. The additional pins is extended with the prospect of the further application of the balance system used in batteries series having at least one hundred of batteries.Next, the software program is accomplished, wherein the communication between the sensor chip and DSP and the processing of the sensor voltage is mainly discussed.Finally, a optimized balance method is to be found due to the further study of Li-ion battery during the design above. As a result, a estimation method of state of charging of the battery and a extend dynamic module is found. So in the end of the paper, a new test method for the parameters relative to SOC is proposed and analyzed.