Thermal management improvement of air-cooled proton exchange membrane fuel cell by using metal foam flow field

The key factor that limits the output performance and commercial applications of air-cooled proton exchange membrane fuel cell (PEMFC) is how to maintain the balance between heat dissipation and water retention. In order to tackle this issue, new cathode flow field with metal foam is experimentally investigated due to superior heat dissipation and water retention capability of metal foam. Experimental results demonstrated that when the height of metal foam is 1 mm and the width of metal foam increases from 1 mm (case 2) to 5 mm (case 6), the temperature of air-cooled PEMFC decreases by 8.4 ℃ under current of 15 A due to the synergic enhancement of heat dissipation and electrochemical performance, indicating the thermal management improvement of air-cooled PEMFC. As the metal foam height increases, however, the thermal management performance of air-cooled PEMFC first increases and then decreases. Therefore, case 6 is considered to be the optimal sample under the constraints of the thermal management performance and compactness of air-cooled PEMFC. By comparing with conventional parallel flow fields with the widths of 1 mm, 3 mm and 5 mm (case 1, case 3 and case 5), the net output performance of case 6 increases by 3.4 %, 8.8 % and 55.1 % and the compression work of case 6 decreases by 69.7 %, 38.3 % and 64.4 % under the same temperature (50 ℃) and current (15 A), which means higher practical application potential and lower parasitic power requirement.