On the modeling of water transport in polymer electrolyte membrane fuel cells

Wu, Hao; Li, Xianguo; Berg, Peter

doi:10.1016/j.electacta.2009.06.070

Cited by 206 publications

(128 citation statements)

References 49 publications

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“…The large difference may (partly) be related to gradients in saturation, which are not captured with Eqs. (8) and (9). Fig.…”

Section: Resultsmentioning

confidence: 99%

“…It was shown that the mentioned expressions (Eqs. (8)- (12)) have a strong impact on the modeling results [8,9]. Thereby, already a small variation of the input parameters may lead to a large variation in the calculated water saturations, associated transport losses and cell performances.…”

Section: àL ð9þmentioning

confidence: 99%

“…(10)-(12) and S À P c (Eqs. (8) and (9)) for a specific GDL material, the parameters n, m, l and P cb have to be fitted with experimental data. Zamel et al [6] for example used the full morphology approach including 3D numerical simulations of water injection and flow in combination with experimental data in order to fit the above mentioned expressions for a commercial GDL material from Toray.…”

Section: àL ð9þmentioning

confidence: 99%

“…Multi-physics modeling can be used to investigate the complex couplings between different transport processes and phase change reactions (including condensation-evaporation) in the PEM fuel cell [3,4,[8][9][10][11][12]. In order to simulate the cell behavior in a reliable and accurate way, a proper description of the relationship between the microstructure (including the morphology of the liquid water phase) and macro-homogeneous properties is urgently requested.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure-property relationships in a gas diffusion layer (GDL) for Polymer Electrolyte Fuel Cells, Part II: pressure-induced water injection and liquid permeability

Holzer

Pecho

Schumacher

et al. 2017

Electrochimica Acta

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Keywords:Gas diffusion layer (GDL) X-ray tomographic microscopy anisotropy liquid permeability short-range effect (SRE) A B S T R A C TThe performance of polymer electrolyte fuel cells (PEFC) strongly depends on a controlled water management within the porous layers. For this purpose we investigate liquid water transport in a commercial gas diffusion layer (SGL 25BA) on the pore scale. X-ray tomography experiments combined with pressure-induced water injection provide 3D images of the liquid water distribution inside the GDL at incremental pressure steps between 0 and 100 mbar.The breakthrough behavior of the liquid phase is highly anisotropic. In through-plane (tp) direction first bubble points appear at the outlet plane already at 5 mbar and the 'breakthrough' then evolves continuously over an extended pressure range up to > 30 mbar. For in-plane (ip) direction the breakthrough is discontinuous and takes place at 27 mbar. Simulations of the intrusion process reveal that the different breakthrough behaviors are mainly triggered by different ip-and tp-transport distances. Short tp-transport distances through the thin gas diffusion layer (ca. 100 mm) are responsible for the characteristic continuous tp-breakthrough behavior, which is thus attributed to a so-called shortrange effect.Dedicated methods for 3D-image analysis adapted to fibrous GDL microstructures were presented in part I. With these methods we quantify all microstructure characteristics that are relevant for liquid permeability. These characteristics of pore and liquid phases include size distributions of bulges and bottlenecks, connectivity, effective volume fractions, geodesic tortuosity, constrictivity and hydraulic radius. Quantitative relationships are established between these microstructure characteristics and the liquid permeability, which provide a better understanding of the underlying microstructure limitations for injection and liquid transport.For the in-plane direction the liquid permeability is limited to roughly a similar extent by tortuosity, constrictivity and effective volume fraction. In contrast, for through-plane direction relatively low volume fractions of the liquid phase put stronger limitations to the liquid permeability than tortuosity, constrictivity and hydraulic radius.The curves for relative permeability vs. saturation (and vs. capillary pressure, respectively) achieved from 3D-analysis reveal complex but characteristic (reproducible) shapes with concave, linear and convex segments. The shape of these segments can be attributed to distinct microstructure effects. In contrast, the conventional macroscopic descriptions from literature cannot capture these complex shapes and the underlying microstructure effects. Future investigations with different GDL materials are necessary in order to understand whether these complex shapes for the relative permeability represent a general feature of gas diffusion layers or if they are specific to the investigated SGL material.

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“…The large difference may (partly) be related to gradients in saturation, which are not captured with Eqs. (8) and (9). Fig.…”

Section: Resultsmentioning

confidence: 99%

Section: àL ð9þmentioning

confidence: 99%

Section: àL ð9þmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Microstructure-property relationships in a gas diffusion layer (GDL) for Polymer Electrolyte Fuel Cells, Part II: pressure-induced water injection and liquid permeability

Holzer

Pecho

Schumacher

et al. 2017

Electrochimica Acta

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“…To be able to compute the ratio of liquid water in the CCL and GDL (s GDL is necessary to obtain the boundary condition of s CCL ), first the general expression for the dynamics of s is developed as introduced in [27,29]:…”

Section: Two-phase Water Modelmentioning

confidence: 99%

Nonlinear predictive control for durability enhancement and efficiency improvement in a fuel cell power system

Luna

Jemeï

Yousfi-Steiner

et al. 2016

Journal of Power Sources

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In this work, a nonlinear model predictive control (NMPC) strategy is proposed to improve the efficiency and enhance the durability of a proton exchange membrane fuel cell (PEMFC) power system. The PEMFC controller is based on a distributed parameters model that describes the nonlinear dynamics of the system, considering spatial variations along the gas channels. Parasitic power from different system auxiliaries is considered, including the main parasitic losses which are those of the compressor. A nonlinear observer is implemented, based on the discretised model of the PEMFC, to estimate the internal states. This information is included in the cost function of the controller to enhance the durability of the system by means of avoiding local starvation and inappropriate water vapour concentrations. Simulation results are presented to show the performance of the proposed controller over a given case study in an automotive application (New European Driving Cycle). With the aim of representing the most relevant phenomena that affects the PEMFC voltage, the simulation model includes a two-phase water model and the effects of liquid water on the catalyst active area. The control model is a simplified version that does not consider two-phase water dynamics.

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