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樋口 雄紀*; 吉宗 航*; 加藤 悟*; 日比 章五*; 瀬戸山 大吾*; 伊勢川 和久*; 松本 吉弘*; 林田 洋寿*; 野崎 洋*; 原田 雅史*; et al.
Communications Engineering (Internet), 3, p.33_1 - 33_7, 2024/02
The automotive industry aims to ensure the cold-start capability of polymer electrolyte fuel cells (PEFCs) for developing fuel cell electric vehicles that can be driven in cold climates. Water and ice behavior is a key factor in maintaining this capability. Previously reported methods for visualizing water and/or ice are limited to small-sized PEFCs ( 
50 cm
), while fuel cell electric vehicles are equipped with larger PEFCs. Here, we developed a system using a pulsed spallation neutron beam to visualize water distribution and identify water/ice phases in practical-sized PEFCs at a cold start. The results show direct evidence of a stepwise freezing behavior inside the PEFC. The produced water initially accumulated at the center of the PEFC and then froze, followed by PEFC shutdown as freezing progressed. This study can serve as a reference to guide the development of cold-start protocols, cell design, and materials for next-generation fuel cell electric vehicles.
吉宗 航*; 樋口 雄紀*; 加藤 晃彦*; 日比 章五*; 山口 聡*; 松本 吉弘*; 林田 洋寿*; 野崎 洋*; 篠原 武尚; 加藤 悟*
ACS Energy Letters (Internet), 8(8), p.3485 - 3487, 2023/08
被引用回数：3 パーセンタイル：66.84(Chemistry, Physical)A multiscale water visualization technique for polymer electrolyte fuel cells was established by using 
multiprobe radiography with pulsed spallation neutron and synchrotron X-ray sources. The three-dimensional water distribution revealed that water back-diffusion from the cathode to the anode significantly contributes to the drainability of practical polymer electrolyte fuel cells toward fuel cell electric vehicles.
Song, F.; 樋口 雄紀*; 日比 章五*; 吉宗 航*; 加藤 悟*; 篠原 武尚
no journal, ,
In this work, we have applied the energy-selective neutron radiography to visualize the freezing and thawing of water in different cavity layers of a fuel cell by taking cross-sectional neutron transmission images, as a preliminary experiment for further operando water/ice identification observations on PEFCs. A miniature size of a fuel cell, which consisted of gas diffusion layers (GDLs) and aluminum frames with gas channels produced by 3D printing technique, was prepared as a model cell sample. This model fuel cell was filled with water and cooled by a Peltier cooler down to -10 degree C. Consecutive high-resolution energy-selective neutron imaging was conducted throughout the freezing process at the RADEN instrument in J-PARC MLF. By taking the ratio of logarithms of neutron transmission between long and short wavelength neutrons, we defined a water/ice identification parameter to confirm freezing of water within the cell. This parameter was spatially resolved on the neutron transmission images to map the water/ice distribution in each layer of the model fuel cell as it was cooled to sub-zero temperatures. In the presentation, we will discuss the spatial and temporal resolution capacities of the high-resolution energy-selective neutron imaging at the RADEN instrument, and show results of the water/ice identification experiments on the cross-sectional observation of the PEFC.
