Design and implementation of a battery module

The battery module (BM), which integrates battery string with peak current charging, constant voltage charging and balancing control together, presents in this paper. In order to obtain smoothly transitive over each charging phase, the small signal model of the peak current charging control was investigated and designed. Furthermore, a low cost 8 bits microcontroller PIC16F877A controls and monitors each operating phase correctly. The battery string consists of 6 lithium ion battery cells in series connected, however, the switched capacitor balancing control scheme adapts only one balancing capacitor with closed loop control and monitor. After analyzing the connection diagram of the balancing circuit breakers, the discharging and charging states with respect to different battery cells or modules were defined. The microcontroller monitors the battery cell voltages and sorts the maximum voltage difference among the battery cells to initiate discharging and charging states for performing charges transfer. A systematic method to design the proposed BM will introduce. Finally, some simulations and experimental results provide to validate the performance of the proposed BM.