Performance improvement in a proton exchange membrane fuel cell with an innovative flow field design

Abstract

The flow field of the proton exchange membrane fuel cell (PEMFC) controls mass and water transfer; it significantly impacts the fuel cell's performance. It is critical to innovate the flow field design for optimizing the performance. This paper proposes a new-designed flow field (NDFF) patterned with the built-in blockage and trap-shape rib association. The novel design was analyzed numerically and experimentally. A three-dimensional isothermal numerical model was first established based on COMSOL software. This model demonstrated that the NDFF transformed the traditional diffusion mass transfer into the optimized diffusion and convection mass transfer combination.Compared with the conventional straight flow field, the effective mass transfer coefficient was considerably improved. Moreover, the new-designed structures enforced cyclical variation of local velocity and pressure, forming forced-convection, which was beneficial for water management. At 0.45AÁcm À2 , the steady-state voltage and the initial dynamic response voltage were increased by 0.08 V and 0.16 V; power density was increased by 20.1%. The experimental results were collected to validate the enhanced performance of PEMFC with the NDFF. Energy efficiency ratio (EER) was proposed as an evaluation criterion; EER results suggested NDFF can improve the net output power. Highlights• A new flow field patterned with built-in blockage and trap shape rib association• Energy efficiency ratio, effective mass transfer coefficient used for evaluation • Steady-state and dynamic performances are greatly improved at an increased Energy efficiency ratioenergy efficiency ratio, flow field, oxygen and water distribution, proton exchange membrane fuel cell | INTRODUCTIONClimate change caused by environmental pollution and global warming is getting great attention; PEMFCs demonstrated outstanding potential for their advantage of zero-pollution. 1-3 Significant progress has been achieved in developing PEMFC's technologies; however, the cost is still one main obstacle that restricts the large-scale commercialization. 4 The cost can be reduced by improving PEMFC's performance. 5 Flow field significantly affects a fuel cell's performance, whose difference among PEMFCs with

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

“…For this study, 70% compressor efficiency 𝜂 was considered [37]. The difference between 𝑊 𝐹𝐶 and 𝑊 𝑃 is the net power (𝑊 𝑛𝑒𝑡 ), which is useful power output of HT-PEMFC, as shown in Equation (18).…”

“…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][17][18][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.…”

Numerical simulation of the polymer electrolyte membrane fuel cells with intermediate blocked interdigitated flow fields

“…These geometric corrections are mainly responsible for inducing a forced convection mechanism due to the over-rib flow to alleviate the mass transfer problem as well as the accumulation of liquid water in the areas under the walls of the flow channels (called ribs). 12 These areas do not share a common contact surface with the flow of reactants, so the transfer of reactants and the discharge of liquid water in these areas is much more limited. To induce transverse forced convection on the rib (over-rib convection), a special design of flow channels is usually used to create a local pressure difference between adjacent flow channels.…”

“…Numerous geometric corrections have been made to conventional flow channels, including hybrid flow fields, angling the channel, changing the curvature of the channel, changing the ratio of rib‐to‐channel width, changing the channel cross‐section, and adding blocks or baffles within the channels. These geometric corrections are mainly responsible for inducing a forced convection mechanism due to the over‐rib flow to alleviate the mass transfer problem as well as the accumulation of liquid water in the areas under the walls of the flow channels (called ribs) 12 . These areas do not share a common contact surface with the flow of reactants, so the transfer of reactants and the discharge of liquid water in these areas is much more limited.…”

The Role of Porous Carbon Inserts on the Performance of Polymer Electrolyte Membrane Fuel Cells: A Parametric Numerical Study

“…Ebrahimzadeh et al [ 39 ] investigated the effects of introducing different types of obstacle including triangular, cylindrical, square, and trapezoidal on the PEMFC performance and the best geometry dimension and arrangement was determined. In a numerical study performed by Huang et al, [ 40 ] a new‐designed flow field patterned with the built‐in blockage and trap‐shape rib association was used in a PEMFC. As compared with the conventional straight flow field, this flow field design considerably enhanced the effective mass transfer coefficient.…”