Time-dependent mechanical behavior of proton exchange membrane fuel cell electrodes

Lu, Zongwen; Santare, Michael H.; Karlsson, Anette M.; Busby, F. Colin; Walsh, Peter

doi:10.1016/j.jpowsour.2013.07.013

Cited by 28 publications

(18 citation statements)

References 22 publications

(19 reference statements)

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“…Plane‐strain modelling assumption was applied due to the large aspect ratio of the PEM fuel cell (MEA thickness of 0.47 mm ( y direction) vs. in‐plane dimension of 15 cm ( z direction)). Two‐dimensional models have been utilized extensively in the literature for prediction of stresses, plastic strains, and failure of PEM fuel cells 9, 10, 14–17, 20–25 as well as for damage propagation in PEM fuel cells 4, 5, 11. Although the use of 3‐D modelling would provide more degrees of freedom for damage propagation (resulting in larger final defects), this 2‐D model still provides valuable insight into defect propagation at reasonable computational costs.…”

Section: Modelling Of Damage In Pem Fuel Cellsmentioning

confidence: 99%

“…Mechanical stresses induced by temperature and relative humidity (hygrothermal) cycles during PEM fuel cell operation play an important role in the initiation and evolution of micro‐scale mechanical defects in the MEA 1, 4, 5, 9–12. The membrane swelling and shrinking in response to the humidity and temperature variations result in in‐plane compressive and tensile stresses in the membrane.…”

Section: Introductionmentioning

confidence: 99%

“…The membrane swelling and shrinking in response to the humidity and temperature variations result in in‐plane compressive and tensile stresses in the membrane. These stresses can be significant enough to reach the yield state of the membrane and hence formation of mechanical defects, particularly after several hygrothermal cycles 9, 10, 13–17. Ex‐situ cyclic studies have shown that this fatigue failure is responsible for mechanical degradation (initiation and propagation of defects) in the MEA, even in the absence of electro‐chemical effects 14, 15.…”

Section: Introductionmentioning

confidence: 99%

“…Their model showed an exponential decrease in membrane life with increasing the RH cycling amplitude. The effect of the strain rate on the initiated crack density in the MEA was studied by Lu et al 10 for a range of humidity and temperatures. Their results suggested that the membrane is more resistant to cracking at higher humidities and strain rates.…”

Section: Introductionmentioning

confidence: 99%

“…Their results suggested that the membrane is more resistant to cracking at higher humidities and strain rates. However, these studies 1, 10, 11 did not include the propagation of micro mechanical defects, which will connect to create large critical defects after several loading cycles.…”

Section: Introductionmentioning

confidence: 99%

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Humidity and Temperature Cycling Effects on Cracks and Delaminations in PEMFCs

Banan

Bazylak

2015

Fuel Cells

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Temperature and relative humidity (hygrothermal) cycles during PEM fuel cell operation can lead to the introduction and exacerbation of micro‐scale mechanical defects. We developed a two‐dimensional finite element model based on cohesive zone theory to describe the delamination propagation at the cathodic membrane/catalyst layer interface due to temperature and hygrothermal duty cycles. Particularly, the effects of hygrothermal cycle amplitudes, relative humidity (RH) distribution profiles, and gas flow channel position were studied. It was found that doubling the hygrothermal cycle amplitude resulted in a 6‐fold increase in fatigue stresses, and a defect length growth to 0,1 mm before reaching the end of the fuel cell life (40,000 cycles). A counter intuitive result was also observed, whereby a crack located within the membrane was found to grow faster than a delamination located at the catalyst layer/membrane interface. When introducing an anode/cathode channel offset, a 2‐fold increase in the rate of delamination propagation was found compared to the case with the aligned anode and cathode channels.

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Section: Modelling Of Damage In Pem Fuel Cellsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Humidity and Temperature Cycling Effects on Cracks and Delaminations in PEMFCs

Banan

Bazylak

2015

Fuel Cells

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Effect of Water Transport on Swelling and Stresses in PFSA Membranes

et al. 2014

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The mechanical durability of membranes used in proton exchange membrane fuel cells (PEMFC) is directly linked to the stresses that evolve in the membrane during fuel cell operation. The stresses are primarily induced due to the swelling of the membrane as it absorbs water, within the mechanical constraints in the fuel cell assembly. Thus, in order to predict the membrane stresses, the water content in the perfluorosulphonic acid (PFSA) membranes is determined numerically via three different absorption models based on experimentally determined water uptake data from the literature. Two models are based on a single, humidity-dependent Fickian transport coefficient for the bulk PFSA membrane. In the third, two transport properties are modeled to account for a possible difference in transport resistance between the bulk membrane and the outer surface. The membrane sorption behaviors characterized from these three models are then independently incorporated in a representative fuel cell finite element model and subjected to a standard relative humidity (RH) protocol designed for measuring mechanical durability of PEMFCs. The results show that the sorption behavior has a significant effect on the membrane stresses and therefore, may impact the lifetime of the membrane.

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Delamination evolution of PEM fuel cell membrane/CL interface under asymmetric RH cycling and CL crack location

Qin

Liu

et al. 2022

Applied Energy

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Time-dependent mechanical behavior of proton exchange membrane fuel cell electrodes

Cited by 28 publications

References 22 publications

Humidity and Temperature Cycling Effects on Cracks and Delaminations in PEMFCs

Humidity and Temperature Cycling Effects on Cracks and Delaminations in PEMFCs

Effect of Water Transport on Swelling and Stresses in PFSA Membranes

Delamination evolution of PEM fuel cell membrane/CL interface under asymmetric RH cycling and CL crack location

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