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A 1+1-dimensional(1+1D) multiphase model of proton exchange membrane fuel cell (PEMFC) is developed to simulate the dynamic behaviors of the fuel cell under various operating conditions. Electrochemical, fluidic, and thermal physical phenomena are taken into account, and the model can accurately describe the multi-physical processes inside the PEMFC. Meanwhile, the water phase change and nitrogen crossover are also considered in this model. The developed model can simulate the fuel cell behaviors in both normal temperature and cold start conditions. Selection of the time step size is discussed, and the solution method of the real-time model is proposed. Computational efficiency is greatly improved by simplifying the multicomponent diffusion inside the membrane electrode assembly (MEA), which results in the shorter calculation time than the simulated physical time. The proposed model is suitable for embedded applications, such as real-time simulation or online diagnostic control. The comprehensive model validation is carried out by comparing the simulation results, including polarization curves, ohmic resistance, local current density distribution, and voltage evolution, under various working conditions of steady state, load change, and cold start, and a good agreement is achieved. Finally, some simulation cases are studied to further demonstrate the simulation ability of the model.

The present research proposes an innovative multi-physics coupled model of different configurations of an integrated coal gasification fuel cell combined cycle (IGFC) system employing Solid Oxide Electrolytic Cell (SOEC) for CO2 capture. Full-system simulation is carried out to examine efficiency. The model incorporates a Solid Oxide Fuel Cell (SOFC), a SOEC, a gas turbine (GT), and multiple recirculation loops operated by two ejectors. The results reveal that compared with traditional power plants, the proposed IGFC system equipped with SOEC can reduce CO2 emission by almost 80%, and operates environmentally beneficial. The efficiency of the system varies greatly depending on the design parameters implemented. The CO2 enrichment phenomenon by SOFC and capture measures of CO2 by SOEC are simultaneously analyzed. In addition, parametric analysis is performed to evaluate the coupling influence of multiple operating parameters on the IGFC system. Recirculation ratios of 0.75 with four times recirculations are found to be the optimal conditions for both SOFC fuel electrode and SOEC air electrode aimed at getting to the highest power generation efficiency and total CO2 capture rate of the system. After systematic optimization of the design parameters, the electrical efficiency and CO2 capture rate of the proposed system could achieve 68.47% and 87.88%, respectively, which are about 20% and 60% greater than those of traditional power plants. Furthermore, after optimizing the control strategy, the fuel utilization rate of the system increases from 63.09% to 83.40%.

Changes are needed to improve the efficiency and lower the CO2 emissions of traditional coal-fired power generation, which is the main source of global CO2 emissions. The integrated gasification fuel cell (IGFC) process, which combines coal gasification and high-temperature fuel cells, was proposed in 2017 to improve the efficiency of coal-based power generation and reduce CO2 emissions. Supported by the National Key R&D Program of China, the IGFC for near-zero CO2 emissions program was enacted with the goal of achieving near-zero CO2 emissions based on (1) catalytic combustion of the flue gas from solid oxide fuel cell (SOFC) stacks and (2) CO2 conversion using solid oxide electrolysis cells (SOECs). In this work, we investigated a kW-level catalytic combustion burner and SOEC stack, evaluated the electrochemical performance of the SOEC stack in H2O electrolysis and H2O/CO2 co-electrolysis, and established a multi-scale and multi-physical coupling simulation model of SOFCs and SOECs. The process developed in this work paves the way for the demonstration and deployment of IGFC technology in the future.

Proton exchange membrane (PEM) fuel cells are a promising candidate as the next-generation power sources for portable, transportation, and stationary applications. Gas diffusion layers (GDL) coated with microporous layers (MPL) are a vital component of PEM fuel cells, providing multiple functions of mechanical support, reactant transport, liquid water removal, waste heat removal, and electron conductance. In this review, we explain several most important aspects in the research and development (R&D) of this fuel cell component, including material characterization, liquid water detection/quantitation, structure reconstruction, fundamental modeling, transport properties, and durability. Specially, the commonly used microstructure reconstruction methods for GDLs are presented and discussed. Visualization techniques for liquid water detection in the GDL and MPL microstructures are described. Major modeling approaches, such as the multiphase mixture (M2) formulation, pore networks model (PNM), lattice Boltzmann method (LBM) and volume of fluid (VOF) approach, are reviewed and explained. Important material properties and parameters that greatly influence two-phase flow and fuel cell performance, and GDL-related material degradation issues are discussed and summarized to further advance on the GDL material design and development.

Relative humidity (RH) cycling during the frequent startup/shutdown (SUSD) process may lead to the generation and propagation of mechanical defects in the polymer electrolyte membrane (PEM) fuel cell. In this study, a 2D finite element model for the evolution of internal defects in PEM fuel cell is established, and the interfacial behavior of the membrane/catalyst layer (CL) is simulated based on the cohesive zone model (CZM), focusing on the RH cycling effect on the membrane/CL delamination evolution. Emphasis is placed on the evolution of membrane/CL delamination when cracks have been generated in the CL. The results show that the existence of the CL crack aggravates the membrane/CL delamination, and the more the position of the CL crack is off-center, the more serious the delamination propagation is. The initial delamination length (IDL) and interface length synergistically affect the interface behavior of membrane/CL. Higher frequency (or shorter period) and greater amplitude of the RH cycle intensify the membrane/CL delamination.

It is well-known that flow field design is of primary importance to optimization of proton exchange membrane (PEM) fuel cell. Traditional channel-rib flow fields, e.g. parallel or serpentine channels, always lead to non-uniform distributions of reactant gas, liquid, current density and so on between the channel and rib regions. Metal foam materials with high porosity (>90%) have been proposed as alternative flow fields for PEM fuel cells. In this study, influences of metal foam flow field on the transport phenomena coupled with the electrochemical reactions in PEM fuel cell are investigated using a three-dimensional (3D) multi-phase non-isothermal model. Specifically, the full morphology of metal foam flow field is taken into account in the 3D simulation after validated against experimental permeability data. The full morphology inclusion enables capture of the detailed gas flow from the flow field into the gas diffusion layer (GDL) and the current collection at the metal foam/GDL interface. In addition, compared with the conventional channel-rib flow fields, the metal foam design greatly increases fuel cell performance in the high current density regime. In addition, the oxygen and current density distributions in PEM fuel cell with the metal foam flow field are more uniform than those in the conventional one. Though the current collection area at the GDL surface is much smaller in the metal foam flow field, the relevant Ohmic loss won't increase significantly due to the improved physical contact by the fine pore structure of metal foam over the GDL.

Hydrogen starvation leads to the extreme deterioration of fuel cell performance due to the induced voltage reversal and carbon corrosion in the anode catalyst layer (ACL) and gas diffusion layer. In this paper, reversal-tolerant anodes (RTAs) with different ACL configurations are proposed, where IrOx/C is used as a water electrolysis catalyst. Experimental results show that the separate IrOx/C catalyst layer of MEA samples, layered reversal-tolerant catalyst-coated membrane (layered-RTA), and reversal-tolerant gas diffusion electrode (GDE-RTA) significantly enhance the reversal tolerance and cell performance compared to conventional anode and common RTA consisting of a homogeneous catalyst layer mixed with IrOx/C and Pt/C (hybrid-RTA). Of these, GDE-RTA possessed a reversal tolerance time of 86 min, a power density of 1.42 W cm−2, and a minimum degradation rate of 2.4 mV min−1, suggesting it to be the best RTA structure. Cyclic voltammetry and electrochemical impedance spectrum were used to detect the properties of each sample. Additionally, the degradation mechanisms of the three RTAs are thoroughly investigated and discussed by means of microstructural characterization through scanning electron microscopy and transmission electron microscopy. This work provides novel ideas for the fabrication of a robust RTA by tuning the ACL configuration, which is practical for the commercialization of fuel cells.

Proton exchange membrane (PEM) fuel cells with an off-gas recirculation anode (ORA) or dead-ended anode (DEA) are widely adopted in engineering. However, those two hydrogen flow arrangements may cause anodic water and nitrogen accumulation in comparison with the flow-through anode (FTA) mode, which causes significant performance degradation. In this paper, a two-dimensional cold-start model is developed with detailed consideration of water phase changes and the nitrogen crossover phenomenon. A simplified electrochemical module is built to calculate the current density distribution in the model. The simulation results are consistent with the experimental data at both subzero temperatures and normal operating temperatures. The effects of hydrogen flow arrangements, flow configurations, and startup strategies are investigated during startup process from subzero to normal operating temperatures. Much less ice is generated in counter-flow cases than in co-flow cases during constant current operation. A relatively lower startup voltage can effectively shorten the cold-start process and enhance the cold-start capacity for the PEM fuel cell. The ORA mode has the best hydrogen flow arrangement due to its general abilities, including higher hydrogen utilization efficiency, higher anodic nitrogen tolerance, better output performance and better startup capability.

A 3D multi-component multi-phase lattice Boltzmann model is developed to study the droplet motion in the flow channel of proton exchange membrane fuel cell. The model is capable of reaching realistic density and viscosity ratio, tunable surface tension with low spurious velocity and is also validated by various benchmark tests in both static and dynamic states. For the first time, the effect of realistic microstructure of gas diffusion layer (GDL) on droplet dynamic behavior is comprehensively studied in terms of comparison with smooth channel, contact angle and droplet size with the motion processes clearly illustrated. The simulation results show the GDL microstructure can amplify the material wettability, affect the motion direction and impede the droplet motion. More hydrophobic GDL can effectively accelerate the transport. However, it is observed the droplet may reach the sidewall due to the presence of GDL and the motion is therefore severely impeded regardless of the GDL contact angle or droplet size, which is hard to avoid but deadly for the water management. For this problem, a novel water management strategy is proposed and the results show the hydrophilic side & top wall can effectively remove the liquid water from the GDL surface, decrease pressure drop and prevent reactant maldistribution.

In this study, the use of metal foam as a flow distributor at cathode is evaluated numerically by a comprehensive three-dimensional solid oxide fuel cell (SOFC) model. The results show that the adoption of metal foam improves the power density by 13.74% at current density of 5000 A m−2 in comparison with conventional straight channel design. It is found that electronic overpotential, oxygen concentration and reaction rates distribute more uniformly without the restriction of ribs. The effects of cathode thickness on the two different flow distributors are compared. Compared with conventional straight channel, the metal foam is found to be more suitable as a distributor for anode supported SOFC with thin cathode gas diffusion layer. Moreover, when metal foam is applied to the fuel cell with a larger reaction area, a more uniform velocity distribution and a lower temperature distribution can be achieved. It is also found that an appropriate permeability coefficient should offer a reasonable pressure drop, which is beneficial for the fuel cell system performance improvement.

This study aims to investigate how multiple parameters affect the two-phase flow in compressed gas diffusion layer (GDL). A stochastic model is adopted to reconstruct the GDL microstructures. Solid mechanics simulations on the reconstructed GDL microstructures are performed, based on the finite element method (FEM). Various pore morphologies and distributions of compressed GDLs are observed. Two-phase flow in GDL is simulated using a volume of fluid (VOF) model. Corner droplet (on the GDL surface) and water flow (emerging from GDL bottom) are considered. It is found that two-phase flow in the GDL is highly influenced by compression, fiber diameter, porosity, and GDL thickness. The results indicate that a larger fiber diameter or higher porosity contributes to the water transport due to larger average pore size. Furthermore, water removal from a thicker GDL is more difficult, whereas water transport in the lower part of a compressed thick GDL is easy.

The deformation and fragmentation processes of single droplet in turbulent velocity flows are compared with the continuous uniform velocity inlet profile flows. Direct numerical simulation (DNS) coupled with volume of fluids (VOF) method is adopted to solve the flow equations and track the liquid–gas interfaces. By varying the turbulence integral length scales, different inlet velocity profiles are generated. Meanwhile, the inlet velocity magnitude changes in a wide range to present the turbulence and Weber number effects on droplet deformation. The temporal and spatial evolution processes of the droplet are taken into consideration. After analyzing the velocity distribution, the motion of the turbulent flow fronts and the scales of the turbulent vortices, the deformation differences between the uniform and turbulent fields are clearly explained. Different from uniform velocity profile, droplet shows an unsteady and unsymmetrical deformation in the turbulence fields. In the later stage, the droplet breakup in the turbulent fields is more intensive and thorough. Due to the velocity fluctuations, the pressure around the droplet is abruptly distributed which causes the droplet to be turned, rotated and side-squeezed. The droplets tend to be turned up and down with the Half integral scale profiles, be turned and rotated with the Quarter while be squeezed sideways with the Tenth. This asymmetrical deformation tendency may stimulate or counteract the transport process. This will help improve the comprehension of the droplet breakup in internal combustion engines and other industrial activities.

The droplet dynamics inside a sinusoidal channel for PEMFC (polymer electrolyte membrane fuel cell) are investigated numerically using the VOF (volume of fluid) method. This study is done for three geometrically different channels corresponding to various non-dimensional sinusoidal distances (50, 25, 12.5, 16.7 and 8.3). The effects of key parameters like sinusoidal distance (pitch-amplitude ratio), radius of curvature and wall contact angle on the droplet removal in the flow channel are investigated. The performance of the sinusoidal as compared to the conventional channel is studied based on droplet removal rate and GDL (gas diffusion layer) surface water coverage. It is found that the droplet removal rate increases with increasing sinusoidal distance and wall contact angle. In addition, decrease in the sinusoidal distance results in a significant reduction in the average droplet speed and gas diffusion layer surface water coverage. It was also observed that broken bits of the droplet stuck on the wall corners accrued with a reduction in the wall contact angle. The curvy nature of the side walls generally induces a secondary flow effect which would be most beneficial in enhanced reactant diffusion and cell performance. It is suggested that the sinusoidal distance and wall contact angle effect on two-phase flow in a channel is highly significant. As such, needs to be considered for water management in sinusoidal channels.

Water and thermal management is of great importance to proton exchange membrane fuel cell. A comfort index is proposed to comprehensively evaluate the water and thermal characteristics in proton exchange membrane fuel cell. It refers to the concept of comfort index in meteorology and selects the cathode liquid water accumulation and anode membrane drying as two basic factors so as to prevent water flooding and low proton conductivity simultaneously. The anode and cathode comfort degrees corresponding to the anode membrane drying and cathode liquid water accumulation, respectively, are quantified and fitted at various operation conditions, of which the parameters in the calculation process are determined utilizing a carefully validated quasi-two-dimensional model. The influences of cathode stoichiometric ratio, operating pressure, coolant temperature difference, cathode relative humidity, coolant temperature, anode recirculating ratio, current density and membrane thickness at wide-range temperature are studied in detail by the comfort index. It is found that the comfort index usually first increases and then decreases with the increment of temperature, because the low water saturation pressure at low temperature makes the water condensation easier and thus leads to water flooding. Compared to analytical simulation models, the comfort index is able to instantly obtain the quantified water and thermal characteristics in proton exchange membrane fuel cell, which is of great significance to the stack design and in-situ system controlling in practical design.

Metal foam (MF) flow field has been the potential reactant gas distributor to improve the water management, gas reactant transport and enhance the performance of proton exchange membrane fuel cells (PEMFCs) owing to its unique porous structure. In this study, the full morphology of MF flow field is reconstructed by geometry representation method, and a two-phase volume of fluid (VOF) model is employed to investigate the gas transport and liquid water dynamics in the MF flow field. The present model is validated with the previous experimental and theoretical studies. The single-phase and two-phase flow behaviors in MF flow field and conventional parallel channel are discussed and compared. The results show that a more uniform and convective-to-electrode gas flow can be obtained in MF flow field. Although the water hold-up phenomenon, i.e., water droplets trapped in pores, is observed and slows down the water transport in MF flow field, the porous structures with favorable connectivity and numerous gas pathways still reduce the “water flooding” in the flow field. In addition, hydrophobic walls (or ligaments) are proved necessary for the water management of a MF flow field.

As a promising renewable energy storage device, the solid oxide electrolysis cell (SOEC) attracts wide attention in the world. In this study, the effect of operating pressure on the co-electrolysis of water and carbon dioxide in SOEC is investigated by a three-dimensional model, in which the reversible water gas shift reaction and direct internal reforming reaction are considered. After comparison with experimental data, the influence of operating pressure on the polarization loss, electrolysis reaction rate, chemical reaction rate and thermal-neutral voltage is also studied in detail. The results show that the cell voltage increases below 8 atm and then decreases with the operating pressure. In addition, the effects of thermal insulation boundary condition, gas flow configuration and gas utilization rate under different operating pressures are also discussed. It is found that the reverse direct internal reforming reaction is activated under the operating pressure higher than 3 atm. Moreover, compared to co-flow arrangement, counter-flow arrangement is more helpful to cell performance improvement at high current densities.

Open-cathode proton exchange membrane fuel cell (PEMFC) is considered as a promising power source for unmanned aerial vehicles and portable applications due to its simple structure and low parasitic power. In this study, the operating condition effects of the open-cathode PEMFC with different cathode flow fields (parallel, pin-type, and metal foam) are investigated experimentally. Polarization curve and electrochemical impedance spectroscopy (EIS) are tested to characterize the cell performance and electrochemical impedance, respectively. The results show that the cell with the metal foam flow field has better performance than that with the other flow fields in the baseline conditions. Although increasing the fan voltage could provide adequate reactant gas and remove excess water, too large air flow rate could reduce membrane water content and decrease temperature that is bad for the cell performance. Increasing the operating temperature would improve the cell performance, but the increase of ohmic resistance caused by higher water evaporation rate cannot be neglected. The cell performance does not increase significantly with increasing the anode backpressure in the low current density region, but decreases with increasing the anode backpressure in the high current density region.

A “3D+1D” PEM fuel cell model is developed in order to implement large-scale simulation with enhanced calculation efficiency. The model consists of the three-dimensional (3D) part and the one-dimensional (1D) part, which are related by adding two extra layers in the middle of the 3D computational domain. Bipolar plate (BP), gas channel (GCH) and gas diffusion layer (GDL) along with the extra layer (EL) form the 3D computational domain. Other components, micro-porous layer (MPL), catalyst layer (CL) and membrane (MEM) are treated as 1D computational domain and integrated into the grids of extra layer. The 3D sub-model solves conservation equations and provides scalar data for the 1D sub-model to obtain solutions of flux equations, in turn updating parameters of the 3D domain to proceed iterations. The “3D+1D” model considers the strongly-coupled physicochemical phenomena comprehensively inside PEM fuel cell including mass transfer (reactant gas and liquid water), electrochemical reaction, membrane water balance and heat transfer. The trade-off between model accuracy and calculation efficiency is evaluated with detail by comparing the simulation results and time cost of the “3D+1D” model with those of the whole 3D model. The calculation speed is found to be greatly boosted via the “3D+1D” approach and acceptable accuracy is obtained at the same time. Specifically, the simulation time can be shortened by 20 folds for the large-scale case in this study. Then, three flow field designs are compared on a 345 cm2 PEM fuel cell domain using the proposed “3D+1D” model, namely the parallel-serpentine design (PS design), the parallel design with dots in the distribution zone (PD design) and the parallel design with dots in the distribution zone and waves in straight-flow zone (PDW design). Owing to the addition of wavy structure, the PDW design gives excellent performance under high current density with low external humidification and stoichiometric ratio due to enhanced gas convection and self-humidification effect. This proves the feasibility and potential of partitioned optimization design on PEM fuel cell flow field, meanwhile emphasizing the suitability of the “3D+1D” modeling approach for occasions where the full morphology of flow field layout should be considered.

This paper evaluates the liquid water at the gas diffusion layer-channel (GDL-channel) interface of reconstructed GDL microstructures with uniform and non-uniform fiber diameters in wave-like channels. A non-uniform GDL microstructure is reconstructed for the first time at the GDL-channel interface to evaluate droplet motion. The three-layer GDL microstructures are generated using the stochastic technique and implemented using the OpenFOAM computational fluid dynamics (CFD) software (OpenFOAM-6, OpenFOAM Foundation Ltd., London, UK). The present study considers the relationship between reconstructed GDL surfaces with varying fiber diameters, wettability, superficial inlet velocity and droplet size. Results show that the droplet detachment and the average droplet velocity decrease with an increase in the fiber diameter as well as the structural arrangement of the fibers. Under the non-uniform fiber arrangement, the removal rate of water droplets is not significantly improved. However, the choice of smaller fiber diameters facilitates the transport of droplets, as hydrophobicity increases even at slight surface roughness. The results also indicate that the average droplet velocity decreases under low inlet velocity conditions while increasing under high inlet velocity conditions. Therefore, the structural make-up of the GDL-channel interface influences the droplet dynamics, and the implementation of a non-uniform GDL structure should also be considered in the GDL designs.

The electrochemical active surface area has a vital influence on the performance of proton exchange membrane fuel cells. In this study, a universal semi-empirical equation of the electrochemical active surface area in the catalyst layer of fuel cells is proposed based on self-designed experiments, aiming to improve the predictive accuracy of numerical models under low humidity conditions. The generalization of this equation is also verified with the other nine catalyst layers of different compositions. At very low water content corresponding to low inlet humidification operations, the electrochemical active surface area is generally low and increases sharply with the increment of water content. When the water content exceeds a certain threshold value, the electrochemical active surface area becomes independent of water content. In addition, the electrochemical active surface area significantly decreases as the operating temperature increases. Consequently, including this newly proposed electrochemical active surface area equation in conventional full-cell models is of significant importance to accurately predict the activation loss and performance of fuel cells under both cold-start and normal operation conditions, especially at low humidification, which is validated against experimental data. In contrast with the conventional constant electrochemical active surface area assumption, this equation improves the model accuracy from about 70% to be higher than 90% under low humidity conditions.

A three-dimensional (3-D) model for planar, anode-supported, solid oxide fuel cell (SOFC) is developed to investigate the effect of operating pressure on cell characteristics. The results show that the elevated operating pressure can improve cell performance by increasing open circuit voltage and reducing activation overpotential, and enhance the electrochemical reaction in the vicinity of electrolyte. Besides, the high pressure can also change the distributions of species and internal reforming reactions. Compared to the case using syngas as fuel, the operating pressure has more significant effects on temperature gradient along flow direction when partly pre-reformed gas is supplied. In addition, efficient control of cell temperature could be achieved by decreasing fuel utilization in the case of partly pre-reformed gas, but this is achieved at the expense of cell efficiency, especially under high pressure condition. Another way to reduce the temperature gradient is to adopt higher air ratio. Moreover, when partly pre-reformed gas is used, the counter-flow configuration has a better performance due to the higher overall temperature.

Two novel cathode channel designs (multi-plates structure channel and integrated structure channel) are proposed and investigated by a three-dimensional multiphase numerical model. The numerical results indicate that the PEMFC with 30° angle, 0.5 mm width and 6.0 mm distance of air-guide plates exhibits the best performance, and the effect of plates angle on PEMFC performance is most significant. Compared with the conventional channel, the novel channel designs are found to be capable of forcing more oxygen towards cathode catalyst layer (CCL) to improve the electrochemical reaction rate. In addition, these two novel channel designs are able to remove more liquid water from PEMFC to effectively avoid from water flooding. According to the simulation results, the maximum improvement of PEMFC net power densities for the multi-plates structure and integrated structure are 4.7% and 7.5%, respectively.

Anode recirculation of proton exchange membrane fuel cell (PEMFC) is considered as an effective way for self-humidification and efficient hydrogen utilization, but nitrogen crossover presents a problem. To investigate the transient characteristics of PEMFC with anode recirculation, a comprehensive quasi-2D non-isothermal transient model is developed. The simulation results show that for a PEMFC initially operated with dry hydrogen, anode recirculation leads to certain level of performance increase in the beginning due to self-humidification effect, and then the performance decreases caused by nitrogen crossover, hydrogen dilution and the increase of anode activation loss. The nitrogen accumulation in anode downstream is severer than upstream, and the performance decline rate decreases with increasing cathode inlet velocity under the simulated operating conditions. The performance and current density distribution uniformity of counter-flow configuration is better than co-flow under low inlet humidity, but the difference becomes smaller with anode recirculation. Anode recirculation and dead-ended anode (DEA) operation both have self-humidification effect, and compared to DEA, the advantages of anode recirculation can be summarized as lower performance decline rate, less chance of local hydrogen starvation and better current density distribution uniformity.

A comprehensive steady-state model is developed to investigate the effects of electrode structure on the performance of solid oxide fuel cell, considering detailed heat and mass transfer processes, as well as electronic and ionic charge transport. The percolation theory is used to evaluate the effective transport properties in electrode. The uniform and non-uniform distributions of electronic/ionic conducting materials in anode/cathode function layer (AFL/CFL) are comprehensively compared. The effects of function layer thickness and particle sizes are found to be different in anode and cathode. The optimal AFL thickness is increased with the increment of particle sizes. The results show that the optimal AFL thickness ranges from 5 μm to 30 μm with relatively small particle sizes (

The 3D (three-dimensional) multi-phase CFD (computational fluid dynamics) model is widely utilized in optimizing water and thermal management of PEM (proton exchange membrane) fuel cell. However, a satisfactory 3D multi-phase CFD model which is able to simulate the detailed gas and liquid two-phase flow in channels and reflect its effect on performance precisely is still not developed due to the coupling difficulties and computation amount. Meanwhile, the agglomerate model of CL (catalyst layer) should also be added in 3D CFD model so as to better reflect the concentration loss and optimize CL structure in macroscopic scale. Besides, the effect of thermal management is perhaps underestimated in current 3D multi-phase CFD simulations due to the lack of coolant channel in computation domain and constant temperature boundary condition. Therefore, the 3D CFD simulations in cell and stack levels with convection boundary condition are suggested to simulate the water and thermal management more accurately. Nevertheless, with the rapid development of PEM fuel cell, current 3D CFD simulations are far from practical demand, especially at high current density and low to zero humidity and for the novel designs developed recently, such as: metal foam flow field, 3D fine mesh flow field, anode circulation etc.

In this study, an enhanced non-isothermal, two-phase 1D analytical proton exchange membrane fuel cell (PEMFC) model is developed, which not only considers the water saturation jump, but also proposes a novel method to analytically solve the water phase changes and couple the liquid and vapor transport together. A stringent model validation procedure is used to show good agreement between the simulated results and the experimental data, taking advantage of the “three-step” and “multi-case” validation methods. It is revealed that the uncertain parameters may deteriorate model reliability and credibility, thus demonstrating the necessity to conduct sensitivity analysis. A multi-parametric screening method i.e. the elementary effect (EE) method based on Monte Carlo experiments is implemented to comprehensively analyze the total 22 uncertain parameters (including geometric, physical and electrochemical parameters), which are finally classified into very sensitive ones, rather sensitive ones and insensitive ones. The cathodic parameters are found more sensitive than the anodic ones, and the parameters of different components may have distinct sensitivity. Besides, whether the effect of each parameter is positive or negative on cell performance is also discussed. Furthermore, three cases with different groups of parameters are presented, which show almost the same polarization curve, and the two-sample Kolmogorov-Smirnov (KS) test is applied to verify the stability difference. It is concluded that those uncertain parameters not only influence the cell performance but also affect the model stability, and hence the effects of varying operating conditions should be taken into account in validation work.