A novel technique for measuring current distributions in PEM fuel cells

Sun, Hong; Zhang, Guangsheng; Guo, Lin; Liu, Hongtan

doi:10.1016/j.jpowsour.2005.09.046

Cited by 85 publications

(47 citation statements)

References 19 publications

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“…Some researchers have investigated the current distribution of PEMFCs during local fuel starvation [50,[77][78][79][80][81][82][83], and Yousfi-Steiner et al [48] provided an excellent review of the causes and consequences of starvation issues. So in this review, we will turn from performance degradation due to local fuel starvation arising from a hydrogen/air interface, and focus in Section 4 on materials improvement and system strategies to mitigate catalyst decay during the startup and shutdown processes.…”

Section: Fuel Starvationmentioning

confidence: 99%

A review on performance degradation of proton exchange membrane fuel cells during startup and shutdown processes: Causes, consequences, and mitigation strategies

Wang

et al. 2012

Journal of Power Sources

253

147

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a b s t r a c tPerformance degradation during startup and shutdown is considered an important issue affecting the durability and lifetime of proton exchange membrane fuel cells (PEMFCs). Due to the high potentials experienced by the cathode during startup and shutdown, the conventional carbon support for the cathode catalyst is prone to oxidation by reacting with oxygen or water. This paper presents an overview of the causes and consequences of performance degradation after frequent startup-shutdown cycles. Mitigation strategies are also summarized, including the use of novel catalyst supports and the application of system strategies to prevent performance degradation in PEMFCs. It is found from the literature review that improvements in catalyst supports to prevent oxidation come at the expense of high cost, and the novel supports developed to date are not sufficient to completely prevent carbon oxidation in fuel cell engines. System strategies, including potential control and reaction gas control, have been developed and applied in fuel cell engines to alleviate or even avoid performance decay. This review aims to provide a clear understanding of the mechanisms related to degradation behaviors during the startup and shutdown processes, thereby helping fuel cell material or system developers in their efforts to prevent performance degradation and prolong the lifetime of PEMFCs.Crown

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Section: Fuel Starvationmentioning

confidence: 99%

A review on performance degradation of proton exchange membrane fuel cells during startup and shutdown processes: Causes, consequences, and mitigation strategies

Wang

et al. 2012

Journal of Power Sources

253

147

View full text Add to dashboard Cite

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“…If optical accessibility to the channels is not feasible, current density distribution or temperature distribution measurements of the cell, also called mapping, can assist in predicting the water concentration profiles across the membrane. The correlation between water, current and temperature was investigated in many studies [164][165][166][167][168][169][170][171][172]. In general, water tends to accumulate near the outlet of the cathode flow channels despite the appearance first of reactant air at the inlets.…”

Section: Water Distribution and Transportmentioning

confidence: 99%

Degradation aspects of water formation and transport in Proton Exchange Membrane Fuel Cell: A review

Ous

Arcoumanis

2013

Journal of Power Sources

123

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link AbstractThis review paper summarises the key aspects of Proton Exchange Membrane Fuel Cell (PEMFC) degradation that are associated with water formation, retention, accumulation, and transport mechanisms within the cell. Issues related to loss of active surface area of the catalyst, ionomer dissolution, membrane swelling, ice formation, corrosion, and contamination are also addressed and discussed. The impact of each of these water mechanisms on cell performance and durability was found to be different and to vary according to the design of the cell and its operating conditions. For example, the presence of liquid water within Membrane Electrode Assembly (MEA), as a result of water accumulation, can be detrimental if the operating temperature of the cell drops to sub-freezing.The volume expansion of liquid water due to ice formation can damage the morphology of different parts of the cell and may shorten its life-time. This can be more serious, for example, during the water transport mechanism where migration of Pt particles from the catalyst may take place after detachment from the carbon support. Furthermore, the effect of transport mechanism could be augmented if humid reactant gases containing impurities poison the membrane, leading to the same outcome as water retention or accumulation.Overall, the impact of water mechanisms can be classified as aging or catastrophic. Aging has a longterm impact over the duration of the PEMFC life-time whereas in the catastrophic mechanism the impact is immediate. The conversion of cell residual water into ice at sub-freezing temperatures by the water retention/ accumulation mechanism and the access of poisoning contaminants through the water transport mechanism are considered to fall into the catastrophic category. The effect of water mechanisms on PEMFC degradation can be reduced or even eliminated by (a) using advanced materials for improving the electrical, chemical and mechanical stability of the cell components against deterioration, and (b) implementing effective strategies for water management in the cell.

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“…A 'segmented' approach has most commonly been used where the flow field (normally anode side) is segmented in order to measure the current distribution in different regions of the cell area, as first demonstrated by Cleghorn et al [84] who used a printed circuit board (PCB) technique. More recently, Sun et al [85] have modified this approach and developed a measurement gasket (see Figure 27) that is inserted between the anode GDL and FFP. This has the advantage of being less intrusive with no need to modify any other components of the fuel cell.…”

Section: Current Distribution Characterisationmentioning

confidence: 99%

Polymer Electrolyte Membrane Fuel Cell (PEMFC) Flow Field Plate: Design, Materials and Characterisation

2010

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Worldwide, there are growing pressures to develop 'carbonfree' societies, where the majority of the energy is produced from renewable technologies, due to climate change [1], adverse health effects [2], fuel resource depletion [3], security of energy supply, economics [4] and increasing tight international legislations [5]. In response to the above issues, many have proposed hydrogen for use as a replacement energy carrier in future energy economies as it produces no greenhouse gases, GHGs (e.g. CO 2 ) when burned or used in a fuel cell with only electricity, heat and water being formed. A fuel cell is an 'electrochemical' device operating at various temperatures (up to 1,000°C) that continuously and efficiently convert chemical energy (from fuel and oxidant) into electrical energy. There are various types of fuel cell including alkaline (AFC), phosphoric acid (PAFC), molten carbonate (MCFC), solid oxide (SOFC) and polymer electrolyte membrane fuel cell (PEMFC) also known as the proton exchange membrane fuel cell (PEMFC) with an efficiency of up to 60% and operating up to 180°C. There are two types of PEMFC: one uses hydrogen as a fuel and the other, methanol -direct methanol fuel cell (DMFC). They both use membrane electrode assemblies (MEAs) which is the heart of the PEM fuel cell where the electrochemical reactions occur. The MEA is a multilayered membrane consisting of a polymeric membrane sandwiched between catalyst layers and gas diffusion layers (GDLs). Currently, the most promising applications for PEM fuel cell are in the automotive sector with trials of buses, cars and motorcycles becoming increasingly common. Others applications include portable, stationary or backup power units. However, the cost, performance and durability still need to be improved if PEMFC is to become a viable alternative energy technology. For example, as 'a rule of thumb', flow field plates (FFPs) constitute 10% (7.7% for a 5 kWnet stack) of the total cost and more than 60% of the weight in PEM fuel cell stacks. For this reason, the weight, volume and cost of the fuel cell stack can be reduced significantly by improving the layout configuration of FFP and use of lightweight materials. Different combinations of materials, flowfield designs and fabrication techniques have been developed for FPPs to achieve the aforementioned functions efficiently, with the main scope of obtaining high performance and economic advantages. Introduction to Flow Field PlatesThe FPP, also known as the monopolar plate (in a single cell) and bipolar plate (BPP, when used in a stack), is one of the many important components of PEM fuel cell stacks as it supplies fuel and oxidant to the MEA, removes water, collects produced current and provides mechanical support for the single cells in the stack (Figure 1) AbstractThis review describes some recent developments in the area of flow field plates (FFPs) for proton exchange membrane fuel cells (PEMFCs). The function, parameters and design of FFPs in PEM fuel cells are outlined and considered in light of their ...

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A novel technique for measuring current distributions in PEM fuel cells

Cited by 85 publications

References 19 publications

A review on performance degradation of proton exchange membrane fuel cells during startup and shutdown processes: Causes, consequences, and mitigation strategies

A review on performance degradation of proton exchange membrane fuel cells during startup and shutdown processes: Causes, consequences, and mitigation strategies

Degradation aspects of water formation and transport in Proton Exchange Membrane Fuel Cell: A review

Polymer Electrolyte Membrane Fuel Cell (PEMFC) Flow Field Plate: Design, Materials and Characterisation

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