Developing a zinc-air fuel cell system for vehicle applications

A zinc-air flow fuel cell system was developed based on the fundamental principles of general zinc-air batteries to study potential techniques of power sources with safety, low-cost, and high energy for vehicle applications. The system consists of a fuel cell stack and a liquid electrolyte flow subsystem, and the stack is recovered by means of changing electrolyte solution and zinc grains after reactants being worked out. An open construction on the top of the fuel cell stack is adopted to facilitate the supplement of zinc. Tests were carried out in a 5-cell zinc-air fuel cell stack with active area of 230 cm² in every cell electrode. The results show that the output power density can reach 170 mW/cm² with a capacity of more than 120 Ah for each cell, which demonstrates the advantage of electrolyte circulation in reducing cell impedances and enhancing performance stability. Therefore, large power zinc-air fuel cell systems for vehicle uses can be made by adding more cells in the stacks according to the power demands. The design can also be used in Al-air and Mg-air fuel cells.