Analysis of PEMFC freeze degradation at −20°C after gas purging

Hou, Junbo; Yu, Hongmei; Zhang, Shengsheng; Sun, Shucheng; Wang, Hongwei; Yi, Baolian; Ming, Pingwen

doi:10.1016/j.jpowsour.2006.07.010

Cited by 123 publications

(67 citation statements)

References 21 publications

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“…[50][51][52] The water holding capacity is defined in this article by the amount of water that can be produced during operation before cell reversal is observed. Since the produced water can freeze into ice, leading to degradation modes such as delamination (film/heave) losses, damage from regular freeze expansion of the ice, and potentially from the extremely rapid freezing of super-cooled water shown to exist, all of which contribute to voltage degradation, it is also referred to as ice (or freeze) tolerance.…”

Section: F1318mentioning

confidence: 99%

Durability of Polymer Electrolyte Membrane Fuel Cells Operated at Subfreezing Temperatures

Macauley

Lujan

Spernjak

et al. 2016

J. Electrochem. Soc.

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The structure, composition, and interfaces of membrane electrode assemblies (MEA) and gas-diffusion layers (GDLs) have a significant effect on the performance of single-proton-exchange-membrane (PEM) fuel cells operated isothermally at subfreezing temperatures. During isothermal constant-current operation at subfreezing temperatures, water forming at the cathode initially hydrates the membrane, then forms ice in the catalyst layer and/or GDL. This ice formation results in a gradual decay in voltage. High-frequency resistance initially decreases due to an increase in membrane water content and then increases over time as the contact resistance increases. The water/ice holding capacity of a fuel cell decreases with decreasing subfreezing temperature (−10 • C vs. −20 • C vs. −30 • C) and increasing current density (0.02 A cm −2 vs. 0.04 A cm −2 ). Ice formation monitored using in-situ highresolution neutron radiography indicated that the ice was concentrated near the cathode catalyst layer at low operating temperatures (≈−20 • C) and high current densities (0.04 A cm −2 ). Significant ice formation was also observed in the GDLs at higher subfreezing temperatures (≈−10 • C) and lower current densities (0.02 A cm −2 ). These results are in good agreement with the long-term durability observations that show more severe degradation at lower temperatures (−20 • C and −30 • C).

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Section: F1318mentioning

confidence: 99%

Durability of Polymer Electrolyte Membrane Fuel Cells Operated at Subfreezing Temperatures

Macauley

Lujan

Spernjak

et al. 2016

J. Electrochem. Soc.

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“…The baseline characterization also revealed that shutdown purge time and energy is mainly constrained by the quantity of liquid water retained in the GDL during operation prior to shutdown. These evaluations were done with new GDL and there is a general concern expressed in open literature that the hydrophobic properties of GDLs degrade over time, thus the saturation properties may change [155]. To evaluate this effect, GM provided GDL from an automotive stack that had ~3000 hours of operation and compared it with neutron radiography to a 200 hour sample.…”

Section: B: Effects Of Gdl Materials Propertiesmentioning

confidence: 99%

Visualization of Fuel Cell Water Transport and Performance Characterization under Freezing Conditions

Kandlikar

Rao

et al. 2010

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“…Since material degradation and lifetime change in a fuel cell are fully dependant on the operating conditions [3][4][5][6][7], the challenge of durability issues is mainly focused on the detailed understanding of failure modes and degradation mechanisms, as well as the systematic approaches to mitigate these problems [8]. Among the fuel cell components, the membrane electrode assembly (MEA) is considered to be the integral element, since it decides the maximum power density obtained from the electrochemical reaction.…”

Section: Introductionmentioning

confidence: 99%

“…Accelerated stress tests are more convenient to execute since they significantly reduce the experiment time while still providing valuable degradation information [16,17]. The accelerated stressors, such as open circuit voltage (OCV) operation [3], load/potential cycling [5], and freeze/thaw cycling [4,6] are the most common stressors used to study fuel cell degradation and failure modes. On the other hand, these test procedures can induce failure to the system that may not be related to actual operational conditions, which makes it hard to understand the exact causes and failure modes of degradation.…”

Section: Introductionmentioning

confidence: 99%

Diagnosis of MEA degradation under accelerated relative humidity cycling

Vengatesan

Fowler

Yuan

et al. 2011

Journal of Power Sources

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The objective of this work is to identify the failure mode diagnosis protocols for polymer electrolyte membrane (PEM) fuel cells with the use of accelerated testing conditions. The single cells used in this work were constructed using commercial Ion Power ® membrane electrode assemblies (MEAs) and the performance degradation was studied under accelerated dynamic reactant relative humidity (RH) conditions. The influence of RH on cell performance was investigated, and a strong dependence of degradation with respect to relative humidity was found. RH cycling was seen to not only cause the gradual decrease in performance at the beginning of cell operation, but it was also related to the rapid decline in performance observed after 330 h operation. This change in degradation rate is seen a change in the material degradation failure mechanism at this point in the operational history of the cell. The increase in cell resistance, membrane crossover, fluoride release rate and decrease in electrochemical surface area (ESA) were also observed with time, and these results were correlated to change in degradation rate. Infra-Red (IR) imaging of an aged MEA was utilized to show varying temperature profiles and outline the possibility of cracks, tears or pinholes in the membrane.

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Analysis of PEMFC freeze degradation at −20°C after gas purging

Cited by 123 publications

References 21 publications

Durability of Polymer Electrolyte Membrane Fuel Cells Operated at Subfreezing Temperatures

Durability of Polymer Electrolyte Membrane Fuel Cells Operated at Subfreezing Temperatures

Visualization of Fuel Cell Water Transport and Performance Characterization under Freezing Conditions

Diagnosis of MEA degradation under accelerated relative humidity cycling

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