A novel development of an unmanned surface vehicle directly powered by an air-cooled proton exchange membrane fuel cell stack

Most compact Unmanned Surface Vehicles (USVs) used in water quality monitoring and maritime surveillance rely on lithium batteries. However, they're only ideal for short missions. This paper first fabricates a novel lightweight, air-cooled, high-power-density Proton Exchange Membrane Fuel Cell (PEMFC) stack with ultrathin steel bipolar plates as the primary power source for a self-made compact USV. This stack consists of 40 single cells and integrates a reliable air-cooled system, operating in parallel with a supercapacitor to enhance its performance. Experimental results show that this PEMFC-powered USV outperforms the main lithium batterypowered counterpart, offering an extended cruising range and better power stability and significantly increasing the cruising range from 8 km to 38 km when the PEMFC stack and the main lithium battery are of similar volume and weight. Integrating a low voltage purging logic with a 0.4 V threshold in the dead-end anode (DEA) mode results in a remarkable hydrogen utilization rate of up to 98%. Moreover, the average voltage of the PEMFC stack with the supercapacitor consistently exceeds that of the stack without the supercapacitor by approximately 0.125 V, mitigating the impact of rapid load changes. The results verify the feasibility of the proposed air-cooled PEMFC-powered USV.