Development of a power management unit for small portable direct borohydride fuel cell–NiMH battery hybrid system

In this study, a small portable fuel cell/battery hybrid system has been developed. The system consists of a single portable direct borohydride/peroxide fuel cell (DBPFC), NiMH battery and power management unit (PMU). The battery has been used as a primary power source and has been discharged at constant load. When its state of charge is reduced, the DBPFC charges the battery and powers the load simultaneously. A DC–DC Boost converter has been used as a PMU. The DBPFC has provided the total power of 0.21 Wh into the system during the charge. During this experimental study fuel (NaBH4) efficiency of 37% has been achieved in the hybrid system, while the system efficiency has been calculated as 34.5%.

► A Direct borohydride fuel cell–NiMH battery hybrid system was configured.
► The fuel cell voltage was regulated by a DC–DC boost converter.
► Relays were controlled by a microcontroller as a power management unit.
► Fuel (NaBH4) efficiency of 37% has been achieved in the hybrid system.
► The system efficiency has been calculated as 34.5%.