Investigating effect of different gas diffusion layers on water droplet characteristics for proton exchange membrane (PEM) fuel cells

Patel, Virat; Battrell, Logan; Anderson, Ryan; Zhu, Ning; Zhang, Lifeng

doi:10.1016/j.ijhydene.2019.05.111

Cited by 21 publications

(13 citation statements)

References 39 publications

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“…In particular, in proton exchange membrane fuel cells (PEMFC) the formation of water droplets is a c oncern as they can cause flooding of the membrane preventing, access of the reactant gases towards the electrodes. 22 Additionally, bubbles in electrochemical processes are known to induce convection and enhance mass transfer rates. 23,24,25,26 Improving the efficiency of existing or emerging electrochemical processes, will require a detailed understanding of the behavior of bubbles in electrochemical systems.…”

Section: Introductionmentioning

confidence: 99%

Influence of Bubbles on the Energy Conversion Efficiency of Electrochemical Reactors

Angulo

Linde

Gardeniers

et al. 2020

Joule

525

374

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Bubbles are known to influence energy and mass transfer in gas evolving electrodes. However, we lack a detailed understanding on the intricate dependencies between bubble evolution processes and electrochemical phenomena.This review discusses our current knowledge on the effects of bubbles on electrochemical systems with the aim to identify opportunities and motivate future research in this area. We first provide a base background on the physics of bubble evolution as it relates to electrochemical processes. Then we outline how bubbles affect energy efficiency of electrode processes, detailing the bubble-induced impacts on activation, ohmic and concentration overpotentials.Lastly, we describe different strategies to mitigate losses and how to exploit bubbles to enhance electrochemical reactions. Context & ScaleElectrochemical reactors will play a key role in the electrification of the chemical industry and can enable the integration of renewable electricity sources with chemical manufacturing. Most large-scale industrial electrochemical processes, including chloro-alkali and aluminum production, involve gas evolving electrodes. The evolution of bubbles at the surface of redox reaction sites often lead to the reduction of the active electrode area, the increase of ohmic resistance in the electrolyte and the formation of undesirable concentration gradients. All of these effects result in energy losses which reduce the efficiency of electrochemical systems. This review synthesizes our current understanding on the relationship between bubble evolution and energy losses in electrochemical reactors. By presenting a thorough account on the state of the research in this area, we aim to provide a common ground for the research community to improve our understanding on the complex processes involved in multiphase electrochemical systems. Increasing our knowledge on the relationship between bubbles and electrochemistry will lead to new strategies to mitigate and exploit bubble-induced phenomena leading to design guidelines for high-performing electrochemical reactors.

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Section: Introductionmentioning

confidence: 99%

Influence of Bubbles on the Energy Conversion Efficiency of Electrochemical Reactors

Angulo

Linde

Gardeniers

et al. 2020

Joule

525

374

View full text Add to dashboard Cite

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“…Droplets emerge into the channel at locations and rates determined by the distribution of water clusters within the GDL. ,,,, Micro X-ray-computed tomography (μCT) experiments show the formation of discrete water clusters in the GDL ,, and spherical droplets on the GDL surface in the channel . Therefore, the water injection rate is into each droplet is specified by the water source velocity u w i or by the operating current based on the available active area ( WL ) where I is the current and M w is the molecular mass of water.…”

Section: Methodsmentioning

confidence: 99%

“…22,26,28,33,50 Micro X-ray-computed tomography (μCT) experiments show the formation of discrete water clusters in the GDL 44,51,52 and spherical droplets on the GDL surface in the channel. 53 Therefore, the water injection rate is into each droplet is specified by the water source velocity u w i or by the operating current based on the available active area (WL)…”

Section: ■ Methodologymentioning

confidence: 99%

Discrete-Particle Model to Optimize Operational Conditions of Proton-Exchange Membrane Fuel-Cell Gas Channels

Niblett

Holmes

Niasar

2021

ACS Appl. Energy Mater.

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Operation of proton-exchange membrane fuel cells is highly deteriorated by mass transfer loss, which is a result of spatial and temporal interaction between airflow, water flow, channel geometry, and its wettability. Prediction of two-phase flow dynamics in gas channels is essential for the optimization of the design and operating of fuel cells. We propose a mechanistic discrete particle model (DPM) to delineate dynamic water distribution in fuel cell gas channels and optimize the operating conditions. Similar to the experimental observations, the model predicts seven types of flow regimes from isolated, side wall, corner, slug, film, and plug flow droplets for industrial temporal and spatial scales. Consequently, two-phase flow regime maps are proposed. The results suggest that an increase in water accumulation in the channel is related to the increase in the water cluster density emerging from the gas diffusion layer rather than the increased water flow rate through constant water pathways. From a modeling perspective, the DPM replicated well volume-of-fluid channel simulation results in terms of saturation, water coverage ratio, and interface locations with an estimated 5 orders of magnitude increase in calculation speed.

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“…The sample is placed between the X-ray source and a detector, which is used to visualise the attenuation of the beam. Utilising this technique, the opaque materials of a cell do not prevent the in situ liquid water formation and transport investigation in the channels and gas diffusion layers [119]. Moreover, it offers the possibility to analyse the cell from the side (in contrast to optical investigations of transparent cells perpendicular to the membrane), which is critical to capture droplet formation and droplet height [120].…”

Section: Neutron Imagingmentioning

confidence: 99%

Modelling Methods and Validation Techniques for CFD Simulations of PEM Fuel Cells

et al. 2021

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The large-scale adoption of fuel cells system for sustainable power generation will require the combined use of both multidimensional models and of dedicated testing techniques, in order to evolve the current technology beyond its present status. This requires an unprecedented understanding of concurrent and interacting fluid dynamics, material and electrochemical processes. In this review article, Polymer Electrolyte Membrane Fuel Cells (PEMFC) are analysed. In the first part, the most common approaches for multi-phase/multi-physics modelling are presented in their governing equations, inherent limitations and accurate materials characterisation for diffusion layers, membrane and catalyst layers. This provides a thorough overview of key aspects to be included in multidimensional CFD models. In the second part, advanced diagnostic techniques are surveyed, indicating testing practices to accurately characterise the cell operation. These can be used to validate models, complementing the conventional observation of the current–voltage curve with key operating parameters, thus defining a joint modelling/testing environment. The two sections complement each other in portraying a unified framework of interrelated physical/chemical processes, laying the foundation of a robust and complete understanding of PEMFC. This is needed to advance the current technology and to consciously use the ever-growing availability of computational resources in the next future.

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Investigating effect of different gas diffusion layers on water droplet characteristics for proton exchange membrane (PEM) fuel cells

Cited by 21 publications

References 39 publications

Influence of Bubbles on the Energy Conversion Efficiency of Electrochemical Reactors

Influence of Bubbles on the Energy Conversion Efficiency of Electrochemical Reactors

Discrete-Particle Model to Optimize Operational Conditions of Proton-Exchange Membrane Fuel-Cell Gas Channels

Modelling Methods and Validation Techniques for CFD Simulations of PEM Fuel Cells

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