Non-isothermal cold start of polymer electrolyte fuel cells

Jiang, Fangming; Fang, Weifeng; Wang, Chao Yang

doi:10.1016/j.electacta.2007.07.032

Cited by 123 publications

(113 citation statements)

References 14 publications

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“…This numerical model was showed in Table 3 with these conservation equations. Jiang et al [87,88] developed a multiphase, three-dimensional model during the cold start process of PEMFCs. This model is developed to describe non-isothermal cold start of a PEMFC and to delineate intricate interactions between ice formation and heat generation during cold start [87].…”

Section: One-dimensional Multi-dimensional Modelsmentioning

confidence: 99%

“…Jiang et al [87,88] developed a multiphase, three-dimensional model during the cold start process of PEMFCs. This model is developed to describe non-isothermal cold start of a PEMFC and to delineate intricate interactions between ice formation and heat generation during cold start [87]. The conclusion was drawn that more water was transported into the membrane leading to less ice formation in CL with the existence of a rising cell temperature.…”

Section: One-dimensional Multi-dimensional Modelsmentioning

confidence: 99%

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A Review on Cold Start of Proton Exchange Membrane Fuel Cells

et al. 2014

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Successful and rapid startup of proton exchange membrane fuel cells (PEMFCs) at subfreezing temperatures (also called cold start) is of great importance for their commercialization in automotive and portable devices. In order to maintain good proton conductivity, the water content in the membrane must be kept at a certain level to ensure that the membrane remains fully hydrated. However, the water in the pores of the catalyst layer (CL), gas diffusion layer (GDL) and the membrane may freeze once the cell temperature decreases below the freezing point (T f ). Thus, methods which could enable the fuel cell startup without or with slight performance degradation at subfreezing temperature need to be studied. This paper presents an extensive review on cold start of PEMFCs, including the state and phase changes of water in PEMFCs, impacts of water freezing on PEMFCs, numerical and experimental studies on PEMFCs, and cold start strategies. The impacts on each component of the fuel cell are discussed in detail. Related numerical and experimental work is also discussed. It should be mentioned that the cold start strategies, especially the enumerated patents, are of great reference value on the practical cold start process. OPEN ACCESSEnergies 2014, 7 3180

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Section: One-dimensional Multi-dimensional Modelsmentioning

confidence: 99%

Section: One-dimensional Multi-dimensional Modelsmentioning

confidence: 99%

A Review on Cold Start of Proton Exchange Membrane Fuel Cells

et al. 2014

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“…9 This technique is technically relevant for commercial applications and has been mostly studied on technical fuel cells or fuel cell stacks. 5,[9][10][11][12][13][14] Such measurements usually aim to validate if the full subzero startup strategy is valid, i.e. if the stack reaches temperatures above zero degrees before failure occurs due to the blocking of the cell by frozen water.…”

mentioning

confidence: 99%

When Size Matters: Active Area Dependence of PEFC Cold Start Capability

Biesdorf

Stahl

Siegwart

et al. 2015

J. Electrochem. Soc.

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Understanding the freezing mechanism of liquid water within polymer electrolyte fuel cells (PEFC) is crucial for its commercialization for mass market. Although various publications investigated the cold start capability of PEFCs, contradictory behaviors during cold starts at freezing temperatures have been published in literature. Interestingly, differences can be mainly identified between large and small size fuel cells: the latter have a significantly higher cold start capability than large size fuel cells. In order to understand the influence of different active areas, we present measurements of cold starts performed with cells sizes of 1 and 50 cm2 using the same materials, including a large count of experiments (>200) on the 1 cm2 cells to perform statistical analysis. The cold start capability is strongly reduced with an increasing size of the active area, and the operating times changes from stochastic values for small cells to reproducible values for large cells. Both effects can be explained by the higher probability of the aggregate state transition from super-cooled water to ice in large cells. Consequently this paper highlights the implications of downscaling PEFCs to draw conclusions for technical relevant cold-starts.

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“…In literature, the following electrochemical and imaging characterization techniques are reported: Electrochemical characterization is mainly performed as isothermal cold start, 5,7,10,14,[19][20][21][22][23][24] freeheating cold start, 8,9,[25][26][27][28][29] cyclic voltammetry 18,[30][31][32] or impedance spectroscopy. 18,30,32 Characterization with imaging has been carried out with light, 7,11,23,24,33 electrons, 15,18,26,30,34 x-rays 10,35 and neutrons.…”

mentioning

confidence: 99%

Statistical Analysis of Isothermal Cold Starts of PEFCs: Impact of Gas Diffusion Layer Properties

Biesdorf

Forner‐Cuenca

Siegwart

et al. 2016

J. Electrochem. Soc.

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In this paper, we present experimental results about the influence of a hydrophobic coating of gas diffusion layers (GDL) and the existence of a micro porous layer (MPL) on the cold start capability of Polymer Electrolyte Fuel Cells (PEFC). The experiments were performed on five different cell configurations with an active area of 1 cm 2 including GDLs of 0, 5, 20 wt% PTFE with and without MPL. Two different experiments were realized: First, a statistical analysis of more than 700 isothermal cold starts was performed to analyze the stochastic freezing behavior of supercooled water inside the fuel cells. Second, a certain number of cold starts were investigated with high-resolution neutron radiography in order to understand the implications of the water distribution on the freezing mechanism. Especially at low coating loads, it was found that cell-to-cell variations are more dominant than variations of the materials. In contrast, a significantly reduced variability between the individual cells as well as a general reduction of the probability of cell failure was observed at high coating loads. The observed effects can be mainly explained by changed morphology of the investigated materials. Regarding the existence of an MPL, only minor effects were observed which could be assigned to a different local distribution of water in the porous layers.

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Non-isothermal cold start of polymer electrolyte fuel cells

Cited by 123 publications

References 14 publications

A Review on Cold Start of Proton Exchange Membrane Fuel Cells

A Review on Cold Start of Proton Exchange Membrane Fuel Cells

When Size Matters: Active Area Dependence of PEFC Cold Start Capability

Statistical Analysis of Isothermal Cold Starts of PEFCs: Impact of Gas Diffusion Layer Properties

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