Research On Single Li-ion Battery Formation Equipment

Li-ion power batteries are used widely at present. But a large amount of energy is wasted during batteries formation (repetitive charge and discharge). Considering this problem we put forward the task of developing high efficient formation equipment and give out the scheme of this task. The scheme makes the DC side of unisolated single PWM rectifier as 350V DC lines. Charger and discharger modules connect to the DC lines. Use this method to charging and discharging single Li-ion battery. This paper is mainly about research and design on charger, discharger and single phase PWM rectifier of this scheme.Firstly, this paper shows the design of discharger. A novel parallel-series topology was put forward. The control circuit was designed and system parameters were figured out. Secondly, charger is designed. The advanced current-doubler synchronous rectifier topology was adopted and its process principle was analyzed. The charging control method and system parameters were worked out. Next part is about the control system of charger and discharger, including hardware circuit and software part. Fourthly, the paper explains the single phase PWM rectifier design. Its principle was analyzed concisely and one-cycle control was adopted. The main circuit and control circuit were designed and the corresponding parameters were calculated. Finally, three hardware modules were put up and experiments have been taken. Test result has proved feasibility of circuit topology structure and controlling scheme and shown correctness of system parameters.