Combining Baffles and Secondary Porous Layers for Performance Enhancement of Proton Exchange Membrane Fuel Cells

Abstract

A numerical study is conducted to compare the current most popular flow field configurations, porous, biporous, porous with baffles, Toyota 3D fine-mesh, and traditional rectangular flow field. Operation at high current densities is considered to elucidate the effect of the flow field designs on the overall heat transfer and liquid water removal. A comprehensive 3D, multiphase, nonisothermal computational fluid dynamics model is developed based on up-to-date heat and mass transfer sub-models, incorporating the complete formulation of the Forchheimer inertial effect and the permeability ratio of the biporous layers. The porous and baffled flow field improves the cell performance by minimizing mass transport losses, enhancing the water removal from the diffusion layers. The baffled flow field is chosen for optimization owing to the simple design and low manufacturing cost. A total of 49 configurations were mutually compared in the design of experiments to show the quantitative effect of each parameter on the performance of the baffled flow field. The results elucidate the significant influence of small geometry modifications on the overall heat and mass transfer. The results of different cases have shown that water saturation can be decreased by up to 33.59% and maximal temperature by 7.91 °C when compared to the reference case which is already characterized by very high performance. The most influencing geometry parameters of the baffles on the cell performance are revealed. The best case of the 49 studied cases is further optimized by introducing a linear scaling factor. Additional geometry modifications demonstrate that the gain in performance can be increased, but at a cost of higher pressure drop and increased design complexity. The conclusions of this work aids in the development of compact and high-performance proton exchange membrane fuel cell stacks.

Numerical investigation of enhanced mass transfer flow field on performance improvement of high‐temperature proton exchange membrane fuel cell

“…Besides the above‐mentioned research, some novel enhanced mass transfer‐FFDs (EMT‐FFDs) have been proposed and proved to be an effective measure to improve the cell performance of LT‐PEMFC [15], such as the blocked [16–19], 3D wave [20, 21], 3D fine‐mesh [22, 23], tapered [7, 24], and stepped [25, 26] FFDs. During LT‐PEMFC operation, the liquid water generated in the cathode blocks the transport of reactants from the channel to the reaction sites in the catalyst layer (CL) and eventually reduces cell performance.…”

Improvement of under‐the‐rib oxygen concentration and water removal in proton exchange membrane fuel cells through three‐dimensional metal printed novel flow fields

“…The other is to design novel geometry of the flow fields, for example, spiral flow field, 14 tapered flow field, 15 wave‐like flow field, 16 baffled flow field 17 and bio‐inspired flow field 18,19 . Moreover, replacement of hollow channels with porous media could also reinforce the water drainage but the manufacture difficulty is extremely high 20 …”

“…18,19 Moreover, replacement of hollow channels with porous media could also reinforce the water drainage but the manufacture difficulty is extremely high. 20 An excellent flow field design should solve the trilemma of performance, pressure drop and manufacture feasibility. Interlaced design, combining the advantages of serpentine and interdigitated flow fields, could generate pressure gradient between adjacent channels so that the mass transport is reinforced through pressure driven transport mechanism at a relatively small pressure drop.…”