Effect of cyclic compression on structure and properties of a Gas Diffusion Layer used in PEM fuel cells

Radhakrishnan, V.; Haridoss, Prathap

doi:10.1016/j.ijhydene.2010.07.009

Cited by 103 publications

(63 citation statements)

References 23 publications

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“…GDL compression occurs during the assembly/disassembly process of the stack [16,17], but also during fuel cell operation due to membrane swelling (an effect that is not considered in this paper) [18e24]. Additionally, the repetitive channel rib pattern of the bipolar plates results in a highly inhomoge neous compressive load, so that while large strains are produced under the rib, typically between 10 and 40% of the initial thickness [28e30], the region under the channels remains approximately at its initial uncompressed state.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear orthotropic model of the inhomogeneous assembly compression of PEM fuel cell gas diffusion layers

García-Salaberri

Vera

Zaera

2011

International Journal of Hydrogen Energy

113

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Keywords:PEM fuel cells Assembly pressure Gas diffusion layers Inhomogeneous compressionNonlinear orthotropic model a b s t r a c t PEM fuel cell assembly pressure is known to cause large strains in the gas diffusion layer (GDL), which results in significant changes in its mechanical, electrical and thermal properties. These changes affect the rates of mass, charge, and heat transport through the GDL, thus impacting fuel cell performance and lifetime. The appropriate modeling of the inhomogeneous GDL compression process associated with the repetitive channel rib pattern is therefore essential for a detailed description of the physical chemical processes that take place in the cell. In this context, the mechanical characterization of the GDL is of special relevance, since its microstructure based on carbon fibers has strongly nonlinear orthotropic properties. The present study describes a new finite element model which fully incorporates the nonlinear orthotropic characteristics of the GDL, thereby improving the prediction of the inhomogeneous compression effects in this key element of the cell. Among other conclusions, the numerical results show that the linear isotropic models widely reported in the literature tend to overestimate the porosity and the partial intrusion of the GDL in the channel region, and may lead to incorrect predictions in terms of interfacial contact pressure distributions.

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Section: Introductionmentioning

confidence: 99%

Nonlinear orthotropic model of the inhomogeneous assembly compression of PEM fuel cell gas diffusion layers

García-Salaberri

Vera

Zaera

2011

International Journal of Hydrogen Energy

113

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“…Matsuura et al [51] found that negligible damage appeared on the GDL when its compressive displacement was 20 lm. However, the breakage of carbon fibers in the GDL was observed at a compressive displacement of 120 lm, as shown in [52] conducted the experiment of 5-cyclic compression of GDL at two different compression pressures (1.7 MPa and 3.4 MPa). They observed both surface and cross-sectional morphologies.…”

Section: Effect Of Compression Forcementioning

confidence: 93%

“…The structural change and/or the loss of PTFE affects the hydrophobicity of the GDL. Radhakrishnan et al [52] reported that the contact angle of the GDL decreased when cyclic compression was applied to the GDL. Bazylak et al [53] also showed that the loss of PTFE creates localized hydrophilic routes that became preferable pathways for the transport of water in the GDL.…”

Section: Effect Of Compression Forcementioning

confidence: 99%

A review of the gas diffusion layer in proton exchange membrane fuel cells: Durability and degradation

et al. 2015

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“…After the invading fluid passes through the mid-point, the sign of the capillary pressure becomes negative, indicating a switch in preferential wettability for the phases. For greater contact angles Equation Radhakrishnan and Haridoss have shown that compression can decrease the contact angle or rather increase the wettability of GDLs and with cyclic compression these changes may become permanent [43].…”

Section: Influence Of Contact Anglementioning

confidence: 99%

The effects of compression on single and multiphase flow in a model polymer electrolyte membrane fuel cell gas diffusion layer

Tranter

Burns

Ingham

et al. 2015

International Journal of Hydrogen Energy

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A two-dimensional study of an idealised fibrous medium representing the gas diffusion layer of a PEMFC is conducted using computational fluid dynamics. Beginning with an isotropic case the medium is compressed uni-directionally to observe the effects on single and multiphase flow. Relations between the compression ratio and the permeability of the medium are deduced and key parameters dictating the changes in flow are elucidated. The main conclusions are that whilst compression reduces the absolute permeability of an isotropic medium, the creation of anisotropic geometry results in preferential liquid water pathways. The most important parameter for capillary flow, in uniformly hydrophobic media, is the minimum fibre spacing normal to the flow path. The effect is less pronounced with decreasing contact angle and non-existent for neutrally wettable media.

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Effect of cyclic compression on structure and properties of a Gas Diffusion Layer used in PEM fuel cells

Cited by 103 publications

References 23 publications

Nonlinear orthotropic model of the inhomogeneous assembly compression of PEM fuel cell gas diffusion layers

Nonlinear orthotropic model of the inhomogeneous assembly compression of PEM fuel cell gas diffusion layers

A review of the gas diffusion layer in proton exchange membrane fuel cells: Durability and degradation

The effects of compression on single and multiphase flow in a model polymer electrolyte membrane fuel cell gas diffusion layer

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