Comparison of PEM Fuel Cell Performance with Metal Foam and Parallel Channel as Flow-Field Gas Distributor

In this paper، metal foams as flow field are used in structures to effectively distribute the gaseous reactants for the electrochemical reactions، reduce weight، save the cost of machining of flow-field channels and enhance performance in the PEM fuel cells. A 3D model is considered and a set of equations consist of continuity، momentum، species and charge together with electrochemical kinetics in the form of single domain is developed and solved numerically. The comparison is made between the PEM unit cell with metal foam and parallel channel as flow-field gas distributor. The results show that after using metal foam flow field designs، the reactant gases transfer and current density increases and gases and current density distribution improves. The performance of the cell with metal foam are similar to cell with paralle channels for low and intermediate current densities; however by increasing current density، the cell with metal foam has better performances، due to omit of ribs effects. Furthermore، metal foam high permeability and foam structure help distributing the reactant gases evenly while keeping pressure loss and therefore parasitic power loss. low.