Performance prediction of scalable fuel cell systems for micro-vehicle applications

Miniature (< 500g) bio-inspired robotic vehicles are being developed for a variety of applications ranging from inspection of hazardous and remote areas to environmental monitoring. Their utility could be greatly improved by replacing batteries with fuel cells consuming high energy density fuels. This thesis surveys miniature fuel cell technologies and identifies direct methanol and sodium borohydride technologies as especially promising at small scales. A methodology for estimating overall system-level performance that accounts for the balance of plant (i.e. the extra components like pumps, blowers, etc. necessary to run the fuel cell system) is developed and used to quantify the performance of two direct methanol and one NaBH4 fuel cell systems. Direct methanol systems with water recirculation offer superior specific power (400 mW/g) and specific energy at powers of 20W and system masses of 150g. The NaBH4 fuel cell system is superior at low power (<5W) because of its more energetic fuel.