Performance analysis of an innovative parallel flow field design of proton exchange membrane fuel cells using multiphysics simulation

The proper design of flow fields has an undeniable influence on the performance and durability of proton exchange membrane fuel cells (PEMFCs). This study aims to propose a novel parallel flow field considering two objectives using a 3D multiphysics CFD simulation. One of these objectives is enhancing the electrochemical performance and the other is lowering the parasitic power loss. To this end, two techniques are utilized to design the structure, the first is tapering the main-channels without any baffles and the second is manipulating the inlet and outlet manifolds. To find the best flow field, 8 structures with different tapering angles are compared with the simple parallel and serpentine flow fields. It is found that the uniformity of water saturation over the catalyst layer (CL) in the proposed tapered parallel flow field is much higher than the simple one. It is also observed that the oxygen transfer from the channels into the CL is more than the tapered-baffled parallel, serpentine, and simple parallel flow-fields, respectively. As a result, the maximum power density increases by 46.1% compared to the simple parallel. The validated results also indicated that the parasitic power loss of the air supply system is 180.1 and 10.9 times lower than serpentine and simple parallel flow fields respectively. A sensitivity analysis is also performed to discover the best operating conditions for this proposed flow field. The results indicated that increasing the cathode stoichiometry is the most effective factor to enhance power density among the other parameters.