Liquid Water Visualization in an Operating PEMFC by Soft X-Ray Radiography

2009 ◽  
Author(s):  
Takashi Sasabe ◽  
Shohji Tsushima ◽  
Shuichiro Hirai ◽  
Katsunori Minami ◽  
Keiji Yada
Keyword(s):  
Current Density ◽  
Liquid Water ◽  
Water Distribution ◽  
Diffusion Length ◽  
Water Removal ◽  
X Ray ◽  
Current Density Range ◽  
Water Accumulation ◽  
Current Densities ◽  
Effective Water

Liquid water distribution in the operational PEMFC was visualized by soft X-ray radiography. To achieve a maximum sensitivity towards liquid water, low electron beam energy in soft X-ray range was chosen. As a result, the spatial resolution of 1 μm and the temporal resolution of 0.5 sec were obtained. In addition, a correlation between the accumulation of water and the reduction of performance in higher current density range was observed. At low current densities, liquid water accumulation was observed under the ribs, because the longer diffusion length for the rib area conduced to a less effective water removal into the vapor phase. With increase of current density, liquid water was also observed under the channels and the reduction of performance with time was observed. These results suggested that the current density under the rib is much less than under the channel and the anisotropy of GDL and the geometry of flow field had a heavy impact on the liquid water distribution and the cell performance.

Structural Properties of Ni-Co Electroplated Coatings Studied by X-Ray Micro-Beam

2014 ◽  
Vol 635 ◽  
pp. 204-207 ◽  
Author(s):  
Ondrej Milkovič ◽  
Mária Hagarová ◽  
Jana Michaliková ◽  
Matúš Horváth
Keyword(s):  
Synchrotron Radiation ◽  
Structural Properties ◽  
Current Density ◽  
Deposition Process ◽  
Transmission Mode ◽  
Structure Parameters ◽  
Electrodeposition Process ◽  
Cu Substrate ◽  
X Ray ◽  
Current Densities

In this article we focused to influence of current density on the structure parameters evaluated by microdiffraction experiment in transmission mode using synchrotron radiation. For this purpose the coatings of Ni-Co alloy were deposited on the Cu substrate using different current densities during the electrodeposition process. The results of the microdiffraction experiment showed the structure uniformity of the coatings along their thickness, as well as changes in the structure parameters depending on the used current density during the deposition process.

RIB/Channel Effect on Cell Performance Under High Current Density Operation

2010 ◽  
Author(s):  
Yuichiro Tabuchi ◽  
Takeshi Shiomi ◽  
Osamu Aoki ◽  
Norio Kubo ◽  
Kazuhiko Shinohara
Keyword(s):  
Water Transport ◽  
Current Density ◽  
Liquid Water ◽  
Water Distribution ◽  
Numerical Study ◽  
High Current Density ◽  
Cell Performance ◽  
High Current ◽  
Numerical Validation ◽  
The Impact

Heat and water transport in polymer electrolyte membrane fuel cell (PEMFC) has considerable impacts on cell performance under high current density which is desired in PEMFC for automobiles. In this study, the impact of rib/channel, heat and water transport on cell performance under high current density was investigated by experimental evaluation of liquid water distribution and numerical validation. Liquid water distribution between rib and channel is evaluated by Neutron Radiography. In order to neglect the effect of liquid water in channel and the distribution of oxygen and hydrogen concentration distribution along with channel length, the differential cell was used in this study. Experimental results show that liquid water under channel was dramatically changed with Rib/Channel width. From numerical study, it is found that the change of liquid water distribution was strongly affected by temperature distribution between rib and channel. In addition, not only heat transport but also water transport through membrane also significantly affected cell performance under high current density operation. From numerical validation, it is concluded that this effect on cell performance under high current density could be due to the enhancement of back-diffusion of water through membrane.

Investigation of Liquid Water Distribution under Temperature Gradient in PEFC Using in-situ X-ray Visualization

2020 ◽  
Vol 98 (9) ◽  
pp. 27-35
Author(s):  
Takahiro Komiyama ◽  
Takashi Sasabe ◽  
Hiroshi Naito ◽  
Katsuyuki Kawamura ◽  
Toshiyuki Suzuki ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Liquid Water ◽  
Water Distribution ◽  
X Ray

In-Situ Observation of the Water Distribution in Porous Layers of PEMFCs by Soft X-Ray Radiography

2010 ◽  
Author(s):  
Takashi Sasabe ◽  
Shohji Tsushima ◽  
Shuichiro Hirai
Keyword(s):  
Water Transport ◽  
Temporal Resolution ◽  
Liquid Water ◽  
Water Distribution ◽  
Transport Phenomena ◽  
Catalyst Layer ◽  
In Situ Observation ◽  
X Ray ◽  
Porous Layers ◽  
Liquid Water Transport

To observe the liquid water distribution in porous layers of an operational Proton Exchange Membrane Fuel Cell (PEMFC) with high spatial and temporal resolution, Laboratory-based soft X-ray microscopy has developed. This system can generate low energy X-ray in the soft X-ray range, and maximum sensitivity towards water is achieved. A point X-ray source with a diameter of less than 1.0 μm and the improved detector optics contribute to realize a spatial resolution of 500 nm and a temporal resolution of 1.0 sec/frame. In addition, in-plane and through-plane observations of an operational PEMFC were carried out. In the in-plane observation test, non-uniform distribution of liquid water in the plane of the catalyst layer was observed, and the importance of appropriate design of the catalyst layer to liquid water transport phenomena was suggested. In the through-plane observation test, liquid water discharge behavior near under the rib area was observed, and the importance of channel wall wettability to liquid water transport phenomena was also suggested.

Visualization of Water Distribution in Operating PEMFC Using X-Ray Microscopy

2009 ◽  
Author(s):  
Jongrok Kim ◽  
Junho Je ◽  
Massoud Kaviany ◽  
Sang Young Son ◽  
MooHwan Kim
Keyword(s):  
Electric Current ◽  
Spatial Resolution ◽  
Current Density ◽  
Water Distribution ◽  
Active Area ◽  
X Ray ◽  
Electric Loader ◽  
Pohang Accelerator Laboratory

In this investigation, X-ray microscopy (7B2) in Pohang Accelerator Laboratory was employed to visualize the water distribution in operating PEMFC which had 2cm × 2cm active area. This X-ray microscopy has 1μm spatial resolution with 1.5mm × 1.2mm view area. Each image spent about 1.3 second, 0.65 second for exposure and about 0.6 second for data read out. The resistance of the electric loader was changed and electric current and voltage was measured during images were recorded. The water distribution in PEMFC was analyzed with this I-V curve. Water distribution was depend on current density and aggregated on interfaces of layers (GDL, MPL, MEA).

Soft X-Ray Investigation on the Effect of Microstructure of PEMFC Porous Layers on Liquid Water Transport

2011 ◽  
Author(s):  
Takashi Sasabe ◽  
Phengxay Deevanhxay ◽  
Shohji Tsushima ◽  
Shuichiro Hirai
Keyword(s):  
Liquid Water ◽  
Water Distribution ◽  
Water Evaporation ◽  
Carbon Paper ◽  
Carbon Cloth ◽  
Cross Sectional ◽  
X Ray ◽  
Porous Layers ◽  
Water Behavior ◽  
Effect Of Microstructure

In order to investigate the effect of microstructure of PEMFC porous layers on the liquid water behavior, liquid water accumulation and discharge behavior in the operating PEMFC was visualized by soft X-ray radiography. The utilization of low energy X-ray made it possible to detect the liquid water behavior in the porous layers with high temporal and spatial resolution, and the cross-sectional imaging can resolve the each components of the PEMFC. The visualization results showed that the liquid water distribution in the carbon paper and the carbon cloth GDL was completely different. The liquid water in the carbon cloth GDL concentrates at the weaves of fiber bundle and was effectively discharged to the channel. In addition, to investigate the effect of the network of pores in more detail, stereo imaging of the liquid water evaporation process from the carbon paper GDL was carried out. These visualization results suggested that the microstructure of the PEMFC porous layers strongly affect the liquid water behavior in the PEMFC.

Sign in / Sign up

Export Citation Format

Share Document