Analysis of Water Balance in PEFC at Transient Operation Mode (Effects of Hydrophobic Treatment and Micro Porous Layer on PEFC Performance at Starting Test Procedure Mode)

Konomi, Toshiaki; Kitahara, Tatsumi; Iwata, Yousuke

doi:10.1299/kikaib.72.764

Cited by 7 publications

(7 citation statements)

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“…For the pore diameter of 3µm, most of the liquid water is expelled to the gas channel in the separator, because the MPL is effective for preventing the back transport of liquid water from the substrate to the electrode. This is effective for a reduction in flooding at the cathode electrode (14) . However, when the MPL pore diameter is too large, the water droplets in the substrate are transported readily from the substrate to the electrode, resulting in an increase in the accumulation of liquid water at the cathode electrode.…”

Section: Influence Of the Mpl On Pefc Performance Under High Humiditymentioning

confidence: 99%

Influences of Microporous Layer Design Parameters for Gas Diffusion Layer on Permeability and PEFC Performance

Kitahara

Konomi

Kazama

2011

JEE

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Gas diffusion layers (GDLs) coated with a microporous layer (MPL) have been commonly used to improve water management properties of polymer electrolyte fuel cells (PEFCs). However, the appropriate pore diameter, thickness and hydrophobicity of the MPL remain unclear. In the present study, the influences of MPL design parameters on permeability and PEFC performance were evaluated. A decrease in the pore diameter of the MPL reduces through-plane permeability significantly, but reduces in-plane permeability only slightly. Under high-humidity conditions, a decrease in the MPL pore diameter is effective for preventing flooding, enhancing PEFC performance. However, when the pore diameter becomes too small, PEFC performance tends to decrease. Reducing the MPL thickness improves in-plane permeability, enhancing the ability of the MPL to avoid flooding. Under low-humidity conditions, a decrease in the MPL pore diameter is effective for preventing drying-out of the MEA. Increasing the MPL thickness is also effective for maintaining the humidity of the MEA. However, when the MPL thickness becomes too large, the transport of oxygen to the electrode through the GDL is deteriorated, lowering PEFC performance.

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Section: Influence Of the Mpl On Pefc Performance Under High Humiditymentioning

confidence: 99%

Influences of Microporous Layer Design Parameters for Gas Diffusion Layer on Permeability and PEFC Performance

Kitahara

Konomi

Kazama

2011

JEE

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“…In the case of the MPL coated GDL, most of the liquid water is expelled to the separator gas channel, because the small hydrophobic pores of the MPL are effective to prevent the back transport of liquid water from the substrate to the electrode. This is effective for the reduction of flooding at the cathode electrode (13) .…”

Section: Test Apparatusmentioning

confidence: 99%

“…However, because the pore diameter of the 20BA GDL without the MPL is relatively large, the water droplets at the substrate are readily back-transported from the substrate to the electrode, as shown in Figure 4 (b), resulting in an increase in the accumulation of liquid water at the cathode electrode (13) . This promotes flooding at the cathode electrode, thereby lowering the PEFC performance, as shown in Figure 3.…”

Section: Influence Of Gdls On Pefc Performance Under High Humiditymentioning

confidence: 99%

Effects of Design Parameters in Paper Type Gas Diffusion Layer on the Performance of Polymer Electrolyte Fuel Cells (Measures to Prevent Flooding and Drying-Up)

Kitahara

Konomi

Murata³

2009

JEE

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The influence of gas diffusion layer (GDL) design parameters on the performance of a polymer electrolyte fuel cell (PEFC) was evaluated using a test apparatus in which the clamp pressure on the cell could be accurately controlled. The PEFC performance varies significantly depending on the humidity of the supplied gas. Under moderate humidity, the PEFC performance is enhanced when using an untreated GDL with high air permeability. Under high humidity, improved performance is achieved using a GDL with PTFE hydrophobic treatment. A microporous layer (MPL) coated GDL significantly reduces flooding on the electrode, resulting in a decrease in the concentration overpotential. This enhances the PEFC performance at high current densities. A substrate with high air permeability for the MPL coated GDL enhances the ability of the MPL to prevent flooding. Under low humidity, the MPL is also effective to prevent drying-up of the membrane electrode assembly (MEA), resulting in enhanced performance. A substrate with low air permeability for the MPL coated GDL is effective for the prevention of drying-up.

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“…In the case of the untreated 25AA GDL, even though the water diffusion resistance is low, liquid water is accumulated in a large portion of the GDL pores, due to its poor hydrophobic characteristics (13). This reduces the diffusion of hydrogen gas to the electrode, resulting in lower PEFC performance compared with 25BA, as shown in Figure 7.…”

mentioning

confidence: 99%

“…This reduces the diffusion of hydrogen gas to the electrode, resulting in lower PEFC performance compared with 25BA, as shown in Figure 7. The 5% PTFE treated GDL (25BA) reduces the accumulation of liquid water in the GDL pores (13), so that the diffusion of both the water vapor and the hydrogen gas is enhanced, resulting in the best PEFC performance. However, when PTFE content in the anode GDL becomes too high, water transport through the anode GDL is reduced.…”

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confidence: 99%

Best Combination of Gas Diffusion Layers for Polymer Electrolyte Fuel Cell under Cathode Condition of Very Low Humidity

Kitahara¹,

Konomi²,

Nakajima

et al. 2008

ECS Trans.

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The present study was carried out to find out the best combination of gas diffusion layers (GDLs) for a polymer electrolyte fuel cell (PEFC) operated under very low-humidity conditions at the cathode and high-humidity conditions at the anode using a test apparatus in which the clamp pressure on the cell could be accurately controlled. For cathode GDLs, it is important to maintain humidity and prevent dehydration of the MEA. A microporous layer (MPL) coating on the low-porosity carbon paper substrate is effective for enhancing PEFC performance. For anode GDLs, however, it is important to increase water transport from the humidified hydrogen gas to the MEA. An anode GDL with the MPL reduces PEFC performance. Hydrophobic treatment by PTFE (polytetrafluoroethylene) loading in the anode GDL is effective for performance enhancement. However, when the PTFE content becomes too high, the water transport properties are reduced, thereby lowering PEFC performance.

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Analysis of Water Balance in PEFC at Transient Operation Mode (Effects of Hydrophobic Treatment and Micro Porous Layer on PEFC Performance at Starting Test Procedure Mode)

Cited by 7 publications

References 0 publications

Influences of Microporous Layer Design Parameters for Gas Diffusion Layer on Permeability and PEFC Performance

Influences of Microporous Layer Design Parameters for Gas Diffusion Layer on Permeability and PEFC Performance

Effects of Design Parameters in Paper Type Gas Diffusion Layer on the Performance of Polymer Electrolyte Fuel Cells (Measures to Prevent Flooding and Drying-Up)

Best Combination of Gas Diffusion Layers for Polymer Electrolyte Fuel Cell under Cathode Condition of Very Low Humidity

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