This thesis investigates the discharging behavior of serial boost-type battery power modules (BPMs). Even though the BPMs are connected in series to cope with a higher output voltage, all batteries in the BPMs can substantially be operated individually so that can realize the balanced discharging control strategy. By which, the battery currents are scheduled in accordance with their state-of-charges (SOCs).A battery power system formed by 10 boost-type BPMs is built, in which a micro controller is used for detecting the loaded voltages, estimating the SOCs, and controlling the duty ratios of the power converters. Experimental results demonstrate the balanced discharging capability of the serial BPMs. In addition, fault tolerance mechanism is introduced to isolate fault or exhausted batteries and keep the system working with a reduced load.