Effect of water phase change on temperature distribution in proton exchange membrane fuel cells

Afshari, Ebrahim; Jazayeri, Seyed Ali; Barzi, Y. Mollayi

doi:10.1007/s00231-010-0647-x

Cited by 18 publications

(12 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nguyen et al 13 confirmed their gravimetric measurements by neutron radiography, while Koido c Present address: et al 14 applied a combination of single phase and two phase 3D Lattice Boltzmann models (LBM) on X-ray tomographic microscopy (XTM) scanned GDL structures and showed that measurement and simulation of saturation dependent permeability had similar shape and magnitude. In contrast to these ex-situ methods, Owejan et al 15 deduced the GDL saturation from neutron radiography of an operating cell with interdigitated flow field.In PEFC multi-physics modeling, water transport in the GDL is typically included based on a macro-homogeneous description, [16][17][18][19][20][21][22][23][24][25] which so far could not properly describe the effects of two-phase water transport and the related influences on mass transport and fuel cell performance. Therefore, more sophisticated models focusing only on the water transport in the GDL domain and its implications on gas transport have been developed, based either on pore network modeling, 26,27 two-phase Lattice Boltzmann models, 14,27-29 or other approaches.…”

mentioning

confidence: 99%

Saturation Dependent Effective Transport Properties of PEFC Gas Diffusion Layers

Rosén

Eller²,

Kang

et al. 2012

J. Electrochem. Soc.

125

122

View full text Add to dashboard Cite

Operating Polymer Electrolyte Fuel Cells (PEFC) under high current density conditions, causes significant losses related to liquid water saturation in the gas diffusion layer (GDL). The blockage of pores inside the material has a strong influence on its effective gas transport properties. Here we report on the combination of in-situ X-ray tomographic microscopy (XTM) of PEFC and the numerical determination of gas transport properties using Lattice Boltzmann and finite difference methods. The GDL domains (Toray TGP-H-060) of two identical cells, each with 11 mm 2 active area, were analyzed in sections of about 0.3 to 0.8 mm 2 size. Saturation levels between 0.1 and 0.4 were found, with higher saturation under the ribs. The saturated and the non-saturated states of the GDL samples were compared in order to quantify the dependence of gas phase permeability and effective relative diffusivity on liquid water saturation. Both these relative measures were found to follow power relationships of (1 − s) λ , where the exponent λ was approximately 3 for all cases except for the in-plane diffusivity where it was closer to 2.Performance of polymer electrolyte fuel cells (PEFC) at high current densities is limited by mass transport losses associated with the presence of liquid water in the porous structures. In the gas diffusion layers (GDL) this issue is particularly relevant.The porous GDL structure allows collecting current under the flow field channels and provides access for the gases under the ribs. 1 This requires a high permeability and relative diffusivity in the pore space and a high conductivity in the solid. GDLs, made from carbon fibers with diameters in the order of typically 6-8 μm, have porosities around 75% and the internal surface is treated with hydrophobing agents. The formation and transport of liquid water in the GDL is thus governed by its internal structure and surface properties, and the presence of liquid water in the pore space of the GDL influences its gas transport properties. At high current density and/or moderate temperature conditions, the oxygen transport in the cathode GDL is particularly affected, which may lead to significant overvoltages. 2,3The effective relative diffusivity of GDLs has been determined with sulphuric acid filled samples and an electrochemical method. 4,5 LaManna et al. 6 have obtained the effective relative diffusivity in a test cell by inducing mass transfer using a concentration gradient of water vapor. These methods however fail to produce saturation dependent results. Opposite to the experimental methods, effective medium theory was used to describe the diffusion through a porous medium consisting of packed spheres. 7 Later, numerical models yielded similar relations particularly for hydrophobic fibrous materials such as the GDL. Tomadakis and Sotirchos 8 used Monte-Carlo simulations in fiber structures and found that the effective relative diffusivity was strongly dependent on the fiber orientation. Nam and Kaviany 9 extended the work of Tomadakis and Sotirchos 8 and...

show abstract

mentioning

confidence: 99%

Saturation Dependent Effective Transport Properties of PEFC Gas Diffusion Layers

Rosén

Eller²,

Kang

et al. 2012

J. Electrochem. Soc.

125

122

View full text Add to dashboard Cite

show abstract

“…According to (13), the thermal entrance length is about 0.030 m (where Re is equal to 150.7). For coolant flow validation in other models, pressure drop along all channels derived from numerical solution is compared with the ones derived from analytical solution.…”

Section: Validation Of Resultsmentioning

confidence: 99%

“…1 small active areas [8][9][10][11]. Some other experimental studies[12][13][14][15] have measured the distribution of temperature and current density simultaneously, showing a strong dependence of the local temperature which is an indication of the local heat generation, on the local current density. The non-uniform distributions of the local heat generation and the local temperature further complicate the cooling process of the PEMFC stacks.…”

mentioning

confidence: 99%

Analytical and numerical study on cooling flow field designs performance of PEM fuel cell with variable heat flux

2016

Self Cite

View full text Add to dashboard Cite

In PEM fuel cells, during electrochemical generation of electricity more than half of the chemical energy of hydrogen is converted to heat. This heat of reactions, if not exhausted properly, would impair the performance and durability of the cell. In general, large scale PEM fuel cells are cooled by liquid water that circulates through coolant flow channels formed in bipolar plates or in dedicated cooling plates. In this paper, a numerical method has been presented to study cooling and temperature distribution of a polymer membrane fuel cell stack. The heat flux on the cooling plate is variable. A three-dimensional model of fluid flow and heat transfer in cooling plates with 15 cm × 15 cm square area is considered and the performances of four different coolant flow field designs, parallel field and serpentine fields are compared in terms of maximum surface temperature, temperature uniformity and pressure drop characteristics. By comparing the results in two cases, the constant and variable heat flux, it is observed that applying constant heat flux instead of variable heat flux which is actually occurring in the fuel cells is not an accurate assumption. The numerical results indicated that the straight flow field model has temperature uniformity index and almost the same temperature difference with the serpentine models, while its pressure drop is less than all of the serpentine models. Another important advantage of this model is the much easier design and building than the spiral models.

show abstract

“…For example, temperatures are correlated closely with transport factors, such as saturation pressure [1], mole fractions in the mixture [2], species diffusivities [3], thermoosmotic diffusivity [4], location of the gaseliquid interface [5], latent heat of phase change [6], cell resistance [7], open circuit voltage (OCV) [8], electrochemical reaction rate [9], and exchange current density [10]. So, the temperature issue, known as the thermal management, must not be lost sight of, when we research on inherent operational mechanism or engineering applications of PEMFCs.…”

Section: Introductionmentioning

confidence: 99%

In situ measurement of temperature distribution within a single polymer electrolyte membrane fuel cell

Lin

Cao

Chen

et al. 2012

International Journal of Hydrogen Energy

View full text Add to dashboard Cite

Effect of water phase change on temperature distribution in proton exchange membrane fuel cells

Cited by 18 publications

References 21 publications

Saturation Dependent Effective Transport Properties of PEFC Gas Diffusion Layers

Saturation Dependent Effective Transport Properties of PEFC Gas Diffusion Layers

Analytical and numerical study on cooling flow field designs performance of PEM fuel cell with variable heat flux

In situ measurement of temperature distribution within a single polymer electrolyte membrane fuel cell

Contact Info

Product

Resources

About