Electrochemical Energy Systems and Power Sources: Fuel Cells

Fuel cells directly convert the chemical energy in fuels into electrical energy. Although fuels other than hydrogen can be used in fuel cells technology development has mainly focused on hydrogen and using oxygen, in the form of air, as oxidant. Most fuel cell power systems comprise a number of components: single cells, stacks, and balance of plant which comprises components that provide feed conditioning water management, thermal management and electric power conditioning and other ancillary functions. This chapter discusses the principle of fuel cell operation, fuel cell systems, polymer electrolyte membrane fuel cells, and alkaline fuel cells. There are three medium to high temperature fuel cells that have been or are under development for commercial applications based on either phosphoric acid (PAFC), molten carbonate (MCFC) and solid oxide (SOFC). One important example of fuel cell classification by electrolyte is the direct alcohol fuel cell (DAFC) and specifically the direct methanol fuel cell (DMFC).