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Kohei Ito Last modified date:2018.02.06

Professor / Hydrogen Utilization Engineering
Department of Mechanical Engineering
Faculty of Engineering


Graduate School
Undergraduate School
Other Organization


E-Mail
Homepage
http://www.mech.kyushu-u.ac.jp/~fcsl/index.html
Introduction of Fuel Cell System Laboratory、member、research、photo gallary .
Fax
092-802-0001
Academic Degree
Study on microscopic transport phenomena at solid-solid interface
Field of Specialization
Electrochemical Systems, Thermal Engineering, Energy Conversion
Outline Activities
R&D:#To establish the water management for PEMFC, I am developing in-situ measurement and observation technique such as using micro-thermocouples. Based on the measurent result, I am investigating the relationship between performance and the phase of water. #Heat balance and process simulation for highly-efficient stationary SOFC system #I investigate the two phase flow inside the water electrolysis cell with numerical simulation and a visualization cell. Especially, we try to figure out how the bobbles produced impacts the electrolyze performance. Based on these analyses, we challenge to make its performance improve. #Electrochemical pump is now under development, which can work with isothermal process and expects to own a higher efficiency than conventional mechanical compressor # Development of reversible cell as buffer to renewable energy fluctuation#Noble frequency analysis and its appropriation to large scale electrochemical cell. #Fuel cells in space. #Combustion in fuel cell.

Education: Thermal energy conversion, hydrogen utilization system, high pressure gas safety engineering, Fuel cell fundamentals. I supervise graduate and undergraduate students.
Research
Research Interests
  • Challenging to reduce electrolysis voltage by superimposing boiling on PEMWE electrochemical reaction


    keyword : Thermodynamic Coupling
    2015.12~2019.03Hydrogen solubility for water under high pressure condition.
  • Fundamental researches for developing middle scale of SOFC system
    keyword : re-circulation, carbon deposition, DRT, sealing
    2013.12~2019.03Hydrogen solubility for water under high pressure condition.
  • Management of fuel cell under vacuum condition
    keyword : convection, liquid cooling, Gas leakage, Crossover
    2015.04~2019.03Hydrogen solubility for water under high pressure condition.
  • Numerical analysis on SOFC system for improvement of its performance.
    keyword : re-circulation, carbon deposition
    2013.12~2019.03Hydrogen solubility for water under high pressure condition.
  • Optimization of high temperature PEM water electrolyzer
    keyword : High temperature, Polymer Electrolyte Membrane
    2013.12~2016.03Hydrogen solubility for water under high pressure condition.
  • Experimental and thermodynamic analysis on the phase state of electrochemically produced water
    keyword : equilibrium
    2011.04~2016.03Hydrogen solubility for water under high pressure condition.
  • Experimental exploration of critical mass transport at triple phase boundary in high-pressure water electrolysis
    keyword : Visualization, bubble, High pressure, PEM, water electrolyzer
    2011.12~2016.03Hydrogen solubility for water under high pressure condition.
  • Mechanism in the degree of super cool in Polymer Electrolyte Fuel Cell
    keyword : hydrophilic, hydrophobic, pore diameter
    2011.04~2013.03Hydrogen solubility for water under high pressure condition.
  • Experimental analysis of electrochemical hydrogen pump
    keyword : polymer electrolyte membrane, cross leak
    2009.09~2013.03Hydrogen solubility for water under high pressure condition.
  • Expermental analysis of hydrogen solubility in water and electrolyte under high pressure condition
    keyword : solubility, hydrogen, phase equilibrium
    2006.04~2011.03Hydrogen solubility for water under high pressure condition.
  • In-situ measurement of hydrogen solubility and diffusivity in polymer material by NMR spectroscopy
    keyword : solubility, polymer, rubber
    2008.04~2012.03Measurement of hydrogen solubility for polymer material.
  • New measurement technique with optical fiber
    keyword : optical fiber, measurement, inside
    2009.04~2011.03.
  • Development of measurement method for PEFC in through-plane direction
    keyword : Temperature, water droplet, visualization cell
    2006.04~2011.03Development of in-situ measurement technique for fuel cell.
  • Development a novel thermoelectric component
    keyword : thermoelectric voltage, nano-structure
    2007.12~2011.03Development of a new thermo-electric device..
  • Solubility measurement of hydrogen gas in polymer with NMR spectroscopy
    keyword : solubility, polymer
    2008.04~2012.03Measurement of hydrogen solubility for polymer material.
  • Measurement and analysis for Hydrogen gas solubility in water under high pressure condition
    keyword : solubility, database, hydrogen gas, phase equilibrium
    2006.04~2010.03Hydrogen solubility for water under high pressure condition.
  • Experimental analysis for the impact of gas-liquid two phase flow on water electrolyzer
    keyword : bubble, differential pressure, visualization
    2005.04~2009.03We analize the effect of two phase flow to the performance of water electrolysis cell..
  • Experimental analysis for water transport in polymer membrane with NMR method
    keyword : water, NMR, diffusivity
    2004.04~2008.03We succeeded in visualizing the water molecule hehavior in polymer electrolyte memblane with NMR method. Based on this visulization technich, we develop new sensor of water molecule for PEMFC..
  • Numerical simulation of heat and electic transport in meso-scale domain
    keyword : Bolzman transport equation, electron, thermoelectric voltage, mean free path
    2004.04~2008.03We developed new numerical simulation code for electron transport, which is based on Boltzmann transport equation. This code make possible to silmulate the performance of electronic devices , whose representative size is mean free path..
  • Study on heat and flow behavior in high-pressure water electrolysis cell
    keyword : high pressure, water electrolyzer, efficiecy
    2004.04~2008.03We developed new simulator for High-pressure Water Electrolysis cell considering hydrogen solubility. With this simulator, we predicted the thermal and flow characteristics, such as temperature distribution. This result help the electrolysis cell to operate..
  • Water management for PEMFC
    keyword : flooding, drying, cell voltage
    2003.07~2011.03We succeeded in visulizing the water droplet in diffusion layer of PEMFC, with novel transparent cell. Comparing with this visulization result, we evalute the two-phase flow simulation for PEMFC..
  • Characterization of SOFC and its combined system by numerical simulation
    keyword : SOFC, combined system, solar energy
    1996.04~2003.03We numerically simulated SOFC-GT combined cycle, and evaluted its system performance..
  • Investigation of heat behavior in secandary battery
    keyword : Lithium ion, Overvoltage, charge, discharge
    1996.04~2003.03We numerically simulated the thermal behavior for Li-ion secondary battery considering exothermic factor, such as overvolatege and entropy change. This simulation well-predicts the temperature change during charging operation of the cell..
  • Characterization of polymer electrolyte cell: water electrolyer, dehumidifier and ozonizer
    keyword : water electrolyzer, ozon, dehumidification
    1996.04~2003.03We experimentally evaluted the performance desicacator, which consists of reverse cycle of PEMFC. In this test, we found out the effects of operation parameter, such as cell temperature, on its performance..
  • Study on PEMFC
    keyword : cell temperature, load current, relative humidity, transient characteristics
    1996.04~2003.03We experimentally evalute the steady and transient state performance of PEMFC, with systematically changing operation parameter. We succeeded in extracting the representative time, which determine the transient characteristic..
  • Experimental and numerical analysis for discharge deNOx process
    keyword : discharge plazma, NOx, energy distribution function, mass spectrometry
    1996.04~2003.03Using mass appearance spectroscopy we measured the radicals in deNOx proccess, where simulated exhoust gas is irradiated by repetitive pulsed discharge. In additon we numerically solved the this process with reation rate equations and Boltzmann transport equation for electron energy distribution. Due to this investigation, we found out the effect of radicals, such as OH, on deNOx performance..
  • Investigation on thermal and electric transport at point contact
    keyword : nano, point contact, thermoelectric voltage, tunneling effect
    1993.04~1996.03We measured the heat and electron transport through microscopic contact, whose diameter is 10nm. As result, we found out that thermo-electromotive force appeard even when the all consititutive materival for this contact was same, and that this phenomena can be explained by non-equilibrium effect..
  • Measurement of thermal boundary resistance between high-Tc superconductive thin film and substrate
    keyword : thermal boundary resistance, bolometer
    1991.04~1993.04We succeeded in measuring the thermal boundary resistance between high-Tc superconductive thin film and its subtrate, with two-strip method..
Current and Past Project
  • High-pressure water electrolysis has the potential to directly and efficiently produce high-pressure hydrogen gas from water at normal pressure. However, some amount of hydrogen gas produced at cathode permeates to anode because of the large pressure difference between them, and this permeation reduces the efficiency. This study challenges to decrease the permeation. Incorporable countermeasures from the system engineering point of view, namely convection, wettability and buoyancy effect will be here evaluated and optimized, leading to extreme enhancement of the departure of hydrogen gas from the triple phase bondary, and leading to the critical performance of high-pressure water electrolyzer.
  • This project test the novel water electrolisys cell, which can produce 35MPa hydrogen gas without compresser. In this test, I analyze the thermal and flow characteristics of this cell, and evalute especially the thermal problem when the cell enlarge.
  • ‘Development of PEMFC simulator considering two phase flow’ Until now, there are several PEMFC simulator considering two phase flow. As a task of PEMFC simulator hereafter, it must support to capture the unsteady phenomena of flooding and drying, which are appeared during cell operation. In addition, the reliability of simulator must be verified rigorously with comparison between simulator and practical cell operation. In this sub-project, we added the energy conservation equation to our PEMFC simulator developed in previous year, and modified it to simulate unsteady state, and then we aimed to obtain the agreement within 10% between simulator and measured value. As result, the simulator showed more practical two-phase flow phenomena, such as distribution of liquid water in GDL. For the unsteady simulation where the load current changes step-wisely, we succeed to obtain transient response of cell voltage which seems to be appeared in practical operation, and we understood it qualitatively with representative times related on the phenomena in cell. In addition, we succeeded to show the relationship between over-voltage and saturation ratio which show the occupation ratio of liquid water to a unit volume. The IV characteristics of simulation agreed with the measured values within 10%. ‘Visualization of flooding in GDL using microscope’ Until now the flooding in GDL, which is important for water management, has not been understood, because GDL is made of opaque material having micro-porous structure and thus it is difficult to apply typical method to measure or visualize the flooding in GDL. Against this background, we executed this sub-subject aiming to visualize the liquid water droplet in GDL, and to obtain where the water droplet is distributed. At first, we designed and made a novel cell, which can enable us to visualize the cross section of GDL. We operated this cell and observed the cross section with digital microscope. As result, we succeed to capture water droplets, which are thought to be caused by cathode reaction. The water droplets were produced at the interface between GDL and catalysis layer, and it spread within GDL under the rib. This success of in-situ capturing the water droplet in GDL is worth on the point to take measure against flooding. Moreover, we made and operated a simple interdigitated cell which has only one path through GDL, and measured the differential pressure at cathode flow channel between inlet and outlet. Assuming that the flow in GDL is Darcy flow, we estimated the saturation ratio in GDL from the differential pressure. With this method using interdigitated cell, we figure out the relationship between saturation and operation parameter such as load current, gas utilization.
  • This project investigated the thermal problem and related technical issue under micro-machine.
  • This project evalute the high temperature steam electrolisys cell, which use solar light as its heat and electric source.
Academic Activities
Books
1. Kohei Ito, Recent Trend in Fuel Cell Science & Technology, Edited by S. Basu, Chapter 5, Water Problem in PEMFC, Springer, (2006), 2006.11.
Reports
1. Hiromitsu Masuda, Atsushi Yamamoto, Kazunari Sasaki, Kohei Ito
"Analysis of impact of water behavior on cell voltage with visualization cell"
J. Fuel Cell Tech., Vol.9, No.2, pp.56-61(2009).
2. Hydrogen Refueling Station in University Campus
Joichi SUGIMURA, Nobuhiro OKADA, Kohei ITO
J. HTSJ, Vol.48、pp.48-53、2009
.
Papers
1. Y. Wakita, Y. Tachikawa, H. Nakajima, K. Ito, Glass shape change during firing for improving the seal of planar SOFCs, ECS Transactions 78 (1), pp.1731-1737 (2017), 78 (1), pp.1731-1737 (2017), 2017.06.
2. YanMing Hao, Hironori NAKAJIMA, Akiko Inada, Kazunari SASAKI, Kohei Ito, Separation and Characterization of Overpotentials in Electrochemical Hydrogen Pump with a Reference Electrode, ECS Transactions, 75 (14) 1155-1163 (2016), 75, 14, 1155-1163, 2016.10, Overpotentials included in electrochemical hydrogen pump are separated with using a reference electrode. Separation result shows that non-ohmic overpotential in cathode is larger than that in anode. This result is also confirmed by electrochemical impedance spectra measurement, which shows impedance spectra of cathode is larger than that of anode. Volmer-Heyrovsky-Tafel mechanism is used to explain the separation result. Simulation result with using this mechanism suggests that reactions in anode and cathode are dominated by different mechanisms, and reaction rate of cathode is 2 orders of magnitude slower than that of anode..
3. Kohei Ito, Takukya Sakaguchi, Yuta Tuchiya, Akiko Inada, Hironori NAKAJIMA, Ryo Saito, Gas Crossover Suppression by Controlling Wettability of Cathode Current Collector, ECS Transactions, 75 (14) 1107-1112 (2016), 75, 14, 1107-1112, 2016.10, Hydrogen gas crossover, which reduces current efficiency, is critical issue in high pressure PEMWE (Polymer Electrolyte Membrane Water Electrolysis). This study proposes controlled wettability current collector, which enhances the detachment of hydrogen gas bubble from the current collector and decreases the crossover. A high pressure operation of a PEMWE cell with visualization clarified that the wettability impacts on the bubble dynamics and changes the current efficiency. Among the current collectors prepared, hydrophilic one indicated higher current efficiency and suggested smaller crossover..
4. Ryohei Torii, Yuya Tachikawa, Kazunari SASAKI, Kohei Ito, Anode gas recirculation for improving the performance and cost of a 5-kW solid oxide fuel cell system, Journal of Power Sources, Volume 325, 1 September 2016, Pages 229–237, Volume 325, 1 September 2016, Pages 229-237, 2016.09.
5. Hua Li, Akiko Inada, Tsuyohiko Fujigaya, Hironori NAKAJIMA, Kazunari SASAKI, Kohei Ito, Effects of operating conditions on performance of high-temperature polymer electrolyte water electrolyzer, Journal of Power Sources, Volume 318, 30 June 2016, Pages 192–199, 10.1016/j.jpowsour.2016.03.108, Volume 318, pp.192-pp.199, 2016.06.
6. Hua Li, Akiko Inada, Hironori NAKAJIMA, 伊藤 衡平, Impact of Cathode Current Collector on High Temperature PEM Water Electrolysis, ECS Transactions 69(18), pp.3-12(2015), 10.1149/06918.0003ecst, volume 69, issue 18, pp.3-pp.12, 2015.12, The effect of cathode current collectors on polymer electrolyte membrane water electrolysis (PEMWE) was evaluated with I-V and I-high frequency resistance (HFR) characteristics. Results reveal that cathode current collectors can impact water electrolysis performance by controlling the amount of water accumulation there, which is proved with overpotential analysis and systematic operation such as feeding additional nitrogen gas to cathode. The hydrophilic cathode current collectors invited better performance than hydrophobic ones, because the hydrophilic ones gives less water accumulation there and enough water content in catalyst coated membrane (CCM). The thickness of cathode current collector did not impact the performance..
7. Yusuke Maeda, Takuya Sakaguchi, Shigeru Tsukamoto, Akiko Inada, Yuta Tsuchiya, Hironori NAKAJIMA, 伊藤 衡平, Analysis and visualization of water flow impact on hydrogen production efficiency in solid polymer water electrolyzer under high-pressure condition, International Journal of Hydrogen Energy, 10.1016/j.ijhydene.2015.03.045, vol.40, pp.5 9 9 5-pp.6 0 0 3, 2015.04, When a solid polymer water electrolyzer (SPWE) is operated under high-pressure conditions,
a large pressure difference occurs between the anode and cathode. This causes
crossover of produced gas, especially hydrogen gas, leading to a decrease in the production
efficiency of an SPWE. As a countermeasure against gas crossover, water should be supplied
into the cathode channel, as well as into the anode channel, because the water flow
will facilitate the drainage of hydrogen gas outside of the cell, resulting in decreased
crossover and increased efficiency of the SPWE. This countermeasure is evaluated by
observing SPWE operation at a pressure of 2 MPa, with a visualization of hydrogen bubbles
in the cathode channel. The evaluation revealed that supplying water into the cathode
channel increases the efficiency by several percent at 0.33 A/cm2. Further, the visualization
of the hydrogen bubbles revealed an enhancement in the separation of hydrogen bubbles
from the surface of the current supplier. This suggests that additional water flow can increase
the hydrogen production efficiency through promoting bubble detachment..
8. Yoshinori Kobayashi, 立川 雄也, Kohei Ito, Kazunari SASAKI, A Solid Polymer Water Electrolysis System Utilizing Natural Circulation, International Journal of Hydrogen Energy, Volume 39, Issue 29, 2 October 2014, Pages 16263-16274, 2014.10.
9. Kohei Ito, Yusuke Maeda, Impact of Water Flow Rate on Current Efficiency in Solid Polymer Water Electrolyzer Under 2 MPa Condition, ECS Transactions Volume 64, Issue 3, 2014, Pages 1019-1028, 2014.09, When solid polymer water electrolyzer (SPWE) is operated under high pressure conditions, large pressure difference forms between anode and cathode. It causes crossover of produced gas, especially for hydrogen gas, and decreases current efficiency of SPWE. Supplying water into cathode channel, in addition to anode, is a countermeasure to suppress the crossover, because the water flow improves to drain the hydrogen gas outside of cell, resulting in a decrease of the crossover and increase of the efficiency. This countermeasure for the crossover is evaluated by a SPWE operation under 2 MPa condition with visualization of hydrogen bubbles in cathode channel. The evaluation revealed that supplying water into cathode channel increases the efficiency by several percent under 0.33 A/cm2. Enhanced detachment of hydrogen bubbles from the surface of current supplier was confirmed by the visualization. It is suggested that this enhancement increases the efficiency. © The Electrochemical Society..
10. Ryosuke Nagahisa, Daiki Kuriya, Hidetaka Muramatsu, Yasuyuki Takata, Kuniyasu Ogawa, Kohei Ito, Measurement System for Solubility and Self-Diffusivity of Hydrogen Gas Dissolved in Polymer Electrolyte Membrane, Journal of The Electrochemical Society, 161 (10) F1070-F1074 (2014), 10.1149/2.0881410jes, volume 161, issue 10, F1070-F1074, 2014.07, The characteristics of hydrogen gas permeation through a polymer electrolyte membrane (PEM) are important in determining the performance of electrochemical systems such as fuel cells and electrolyzers. However, the only available data related to these characteristics are those for the hydrogen permeability, which were obtained from measurements under a given pressure difference through the PEM. Although we can derive the solubility and self-diffusivity from the permeability, the derivation requires a mathematical procedure, such as providing a gas transport model and fitting experimental data with theoretical data from the model. In this study, we developed a measurement system that uses nuclear magnetic resonance and can quantify both the solubility and self-diffusivity in a rather straightforward manner. The system allows us to measure these two properties when hydrogen gas is dissolved in a dry Nafion membrane under a hydrogen gas pressure of up to 1 MPa at room temperature. The solubility increases linearly with increasing pressure, and the solubility coefficient is (1.3 ± 0.13) × 10−5 mol/(cm3MPa). The self-diffusivity shows a constant value of (2 ± 0.4) × 10−6 cm2/s regardless of the pressure..
11. Yuji Ishikawa, Masahiro Shiozawa, Masaaki Kondo, Kohei Ito, Theoretical analysis of super-cooled state of water generated below the freezing point in a PEFC, International Journal of Heat and Mass Transfer, Vol.74, July 2014, 10.1016/j.ijheatmasstransfer.2014.03.038, July2014, 74, 215-227, 2014.04, The water produced in a proton exchange fuel cell can exist in supercooled states during cold start operation. Visualization studies of unit cells under cold start conditions have confirmed that supercooled states exist in the cells and that they are eventually released. However, these supercooled states have not been quantitatively characterized, and it is difficult to predict them. Moreover, it has not been clarified what determines the supercooling degree and the release of supercooled states in each part of the cells, such as the gas flow channels, gas diffusion layers, and catalyst layer. In this work, a theoretical model was developed to predict the release of supercooled states on the basis of heterogeneous nucleation theory and by considering the surface wettability of the porous media in the cells. This model was evaluated through comparison to our in situ visualization study of a cell during a cold start. The developed model reproduced the supercooled state in the cell well, specifically its release time, and quantitatively clarified the impact of the pore diameter and wettability on the supercooled states.

.
12. Kuniyasu Ogawa, Tomoyuki Haishi, Kohei Ito, Differences in Drying/WettingWater Transfer Resistance Through a Platinum Catalyst Layer of a PEMFC Electrode Membrane, Journal of The Electrochemical Society, Journal of The Electrochemical Society, 161 (1) F239-F245 (2014), 2014.01, In order to understand the water transport phenomenon in a membrane electrode assembly (MEA), the water transfer resistance
through a platinum catalyst layers (CL) is required. In this study, the overall water transfer resistance through the CL is taken as the
sum of the resistance to charge/discharge water from the surface of ionomer in the CL and the resistance for water to pass through the
ionomer in the CL. The value of this quantity for a CL that is 4 μm thick and is coated on a 178 μm thick Nafion 117, was estimated.
The MEA was dried/wetted by supplying gas with controlled humidity to the surface of the MEA. The water concentration contained
in the PEM was measured by nuclear magnetic resonance (NMR) using a small detection coil. The rates of drying/wetting of the
MEA were calculated from time-dependent changes of the water concentration measured in the PEM. The overall water transfer
resistance through a CL was estimated by comparing experiment and analytical results based on the analytical model. As a result,
the overall water transfer resistances through the 4 μm thick CL during drying and wetting were 0–3 × 104 and 10 ± 6 × 104 s/m,
respectively.
13. Sang-Kun Lee, Kohei Ito, Cross-Sectional Visualization and Analysis of Droplet Behavior in Gas Flow Channel in PEFC, Journal of The Electrochemical Society, 161 (1) F58-F66 (2014), Journal of The Electrochemical Society, 161 (1) F58-F66 (2014), 2014.01, A new cross-sectional visualization cell in which a transparent material is not embedded in the separator was developed to observe water droplet behavior in a flow channel and to analyze the impact of the channel and gas diffusion layer (GDL) surface on the behavior. A specific GDL and separator pair was chosen so that the surface of the GDL was more hydrophobic than that of the separator, where the contact angle difference between them was approximately 27◦. With this GDL and separator pair, a droplet formed in the channel does not touch the GDL surface. This specific pair also makes the droplet smaller and causes less of a pressure drop through the channel, leading to superior drainage from the channel. A theoretical analysis based on the force balance surrounding a droplet explains this superior drainage. The reason is that the combination of the hydrophobic GDL and hydrophilic
separator reduces the adhesion force on the droplet, promoting water drainage..
14. Kohei Ito, Design and characterization of high pressure electrochemical hydrogen pump, 19th World Hydrogen Energy Conference2012, 2012.06, Hydrogen energy society, especially hydrogen gas station for FCV, needs stable supply of high pressure hydrogen gas at 40 MPa or more than that. However, conventional booster, which is mechanically driven, has rather low reliability. Against this situation we expect electrochemical booster called as hydrogen pump, where hydrogen gas is pressurized by the immigration of the gas from anode to cathode through DC-applied MEA (membrane electrode assembly). The hydrogen pump is predicted that it has high reliability because of no mechanical links and that it has high efficiency in principle because of isothermal process. Here we show the minimum power of hydrogen pump and the concerns inherently existed in the pump, such as back diffusion of hydrogen gas pumped and breaking of MEA. Moreover, a prototype model of the hydrogen pump up to 2 MPa is designed and fabricated, and voltage and current efficiency obtained from the first running of the pump are presented. .
15. Kohei Ito、Tomoaki Hagio、Akira Matsuo、Yasushi Iwaisako、Osamu Nakabeppu, EXPERIMENTAL ANALYSIS OF THERMAL AND ELECTRIC TRANSPORT CHARACTERISTICS OF NANO-GAPS, Proceedings of the ASME/JSME 2011 8th Thermal Engineering Joint Conference、AJTEC2011 , CD-ROM, 2011.03.
16. Hiromitsu Masuda, Atsushi Yamamoto, Kazunari Sasaki, Sangkun Lee, Kohei Ito, A visualization study on relationship between water-droplet behavior and cell voltage appeared in straight, parallel and serpentine channel pattern cells, Journal of Power Sources,Vol.196, pp.5377-5385(2011), Vol.196, pp.5377-5385(2011), 2011.02.
17. Sang-Kun Lee, Kohei Ito, Kazunari Sasaki, A Cross-sectional Observation of Water Behavior in the Flow Channel in PEFC, ESC Transactions, Vol. 33, Issue 1, (2010), 2010.10.
18. Kazunari Sasaki, Fumiaki Takasaki, Zhiyun Noda, Shingo Hayashi, Yusuke Shiratori, Kohei Ito, Alternative Electrocatalyst Support Materials for Polymer Electrolyte Fuel Cells, ESC Transactions, Vol. 33, Issue 1, (2010), 2010.10.
19. Yasuo YOKOUCHI, Kuniyasu OGAWA, Tomoyuki HAISHI and Kohei ITO , Current-Distribution Measurement in Polymer Electrolyte Water Electrolysis Equipment and Polymer Electrolyte Fuel Cell using NMR Sensor, Special Issue on the Second Internatinal Forum on Heat Transfer, Journal of Thermal Science and Technology, Vol.4, No.4, pp.462-468(2009), 2009.12.
20. K. Araki, J. Yamamoto, Y. Shiratori, K. Ito, and K. Sasaki, Performance and Long-term Durability of Nanostructured Ni Anodes Doped with Transition Metals Prepared by Spray Mist Dryer, ECS Transactions, Vol.25, No.2, pp.2039-2048(2009), 2009.10.
21. R. R. Liu, S. H. Kim, Y. Shiratori, T. Oshima, K. Ito, and K. Sasaki, The Influence of Water Vapor and SO2 on the Durability of Solid Oxide Fuel Cells, ECS Transactions, Vol.25, No.2, pp.2859-2866(2009), 2009.10.
22. K. Haga, Y. Shiratori, K. Ito, and K. Sasaki, Chemical Degradation and Poisoning Mechanism of Cermet Anodes in Solid Oxide Fuel Cells, ECS Transactions, Vol.25, No.2, pp. 2031-2038(2009), 2009.10.
23. Sang-Kun Lee, Kohei Ito, and Kazunari Sasaki, Temperature Measurement of Through-plane Direction in PEFC with a Fabricated In-line Thermocouple and Supporter
, ESC Transactions, Vol.25, No.1, pp.495-503(2009), 2009.10.
24. Kohei Ito, Sangkun Lee, Atsushi Yamamoto, Masaaki Hirano, Hidetaka Muramatsu, Kazunari Sasaki and Kuniyasu Ogawa, KEYNOTE PAPER: IN-SITU MEASUREMENT IN THROUGH-PLANE DIRECTION IN PEMFC, Proceedings of the Seventh International ASME Conference on Nanochannels, Microchannels and Minichannels, ICNMM2009-82132(2009), 2009.06.
25. A. Masao, S. Noda, F. Takasaki, K. Ito, and K. Sasaki, Carbon-free Pt Electrocatalysts Supported on SnO2 for Polymer Electrolyte Fuel Cells, Electrochem. Solid-State Lett., Vol.12, No.9, pp.B119-B122(2009), 2009.06.
26. Sang-Kun Lee, Kohei Ito, Toshihiro Ohshima, Shiun Noda, and Kazunari Sasaki, In-situ Measurement of Temperature Distribution across a Proton Exchange Membrane Fuel Cell, Electrochemical and Solid-State Letters, Vol.12, No.9, pp.B126-130(2009), 2009.06.
27. Development of a measurement technique for current-density in PEFC using planar surface coil as a NMR signal detector First report: One-dimensional measurement of current-density generating in PEFC
.
28. Numerical analysis of thermoelectric phenomenon by Boltzmann transport equation with discretization of all wave-number spaces.
29. Yasuo Yokouchi, Kuniyasu Ogawa, Tomoyuki Haishi and Kohei Ito, Current-Distribution Measurement in PEFC Using NMR Sensors ; Experimental and Theoretical Results under Uniform Electric Power Generation Condition, Proceedings of the Seventh JSME-KSME Thermal and Fluids Engineering Conference, (2008), 2008.10.
30. K. Haga, Y. Shiratori, K. Ito, and K. Sasaki, Chlorine Poisoning of SOFC Ni-Cermet Anodes, J. Electrochem. Soc., Vol.155, No.12, B1233-B1239 (2008), 2008.09.
31. K. Haga, S. Adachi, Y. Shiratori, K. Ito, and K. Sasaki, Poisoning of SOFC Anodes by Various Fuel Impurities, Solid State Ionics, Vol.179, No.27-32, pp.1427-1431 (2008), 2008.09.
32. Yasuo YOKOUCHI, Kuniyasu OGAWA, Tomoyuki HAISHI and Kohei ITO, CURRENT-DISTRIBUTION MEASUREMENT IN MEMBRANE ELECTRODE ASSEMBLY UNDER WATER
ELECTROLYSIS CONDITION USING NMR SENSOR, Proceedings of the 2nd International Forum on Heat Transfer , pp.94-97(2008), 2008.09.
33. Hiromitsu Masuda, Kohei Ito, Toshihiro Oshima, Kazunari Sasaki, Comparison between numerical simulation and visualization experiment on water behavior in single straight flow channel polymer electrolyte fuel cells, Journal of Power Sources, Vol.177, No.2, pp.303-313(2008), 2008.03.
34. Kohei Ito; Kensuke Ashikaga; Hiromitsu Masuda; Toshihiro Oshima; Yasushi Kakimoto; Kazunari Sasaki , Estimation of flooding in PEMFC gas diffusion layer by differential pressure measurement, Journal of Power Sources, Vol.175, No.2, pp.732-738(2008), 2008.01.
35. S. H. Kim, T. Ohshima, Y. Shiratori, K. Ito, and K. Sasaki, Effect of Water Vapor and SOx in Air on the Cathodes of Solid Oxide Fuel Cells, Materials Research Society Symposium Proceedings, Vol.1041, pp131-137 (2007), 2007.11.
36. Kohei Ito, Tomohiko Miyazaki, SangKun Lee, Kazunari Sasaki, Hiromitsu Masuda, Kyushu University, Visualization of flooding in GDL with sectional model cell, 2007 Fuel Cell Seminar and Exposition, San Antonio, Texas, USA, October 15-19, 2007, 2007.10.
37. Kohei Ito, Tomohiko Miyazaki, SangKun Lee, Kazunari Sasaki, Hiromitsu Masuda, Visualization of flooding in GDL with sectional model cell, 2007 Fuel Cell Seminar and Exposition, San Antonio, Texas, USA, October 15-19, 2007, 2007.10.
38. Kuniyasu Ogawa, Tomoyuki Haishi and Kohei Ito, Local water-content measurement of PEM for fuel cell applications using planar surface coils, Proceedings of the 9th ICMRM in Aachen, 2-7 September, 2007, Aachen, Germany
, 2007.09.
39. Kuniyasu OGAWA, Naruhiko SHIRAI, Kohei ITO, Tomoyuki HAISHI, Water-Content Measurement in Polymer Electrolyte Membrane Using MRI for Estimation of Diffusion Coefficient of Water, Proceedings of The 8th Asian Thermophysical Properties Conference, Fukuoka, Japan, No.145(2007), 2007.08.
40. Estimation of flooding in PEMFC gas diffusion layer by differential pressure measurement
.
41. Y. Kawasoe, T. Kuroki, H. Kusaba, K. Ito, Y. Teraoka, and K. Sasaki, Preparation and Electrochemical Activities of Pt-Ti Alloy PEFC Electrocatalysts, J. Electrochem. Soc., Vol.154, No.9, pp.B969-B975(2007), 2007.07.
42. Hiromitsu Masuda, Kohei Ito, Toshihiro Oshima, Kazunari Sasaki, Visualization and 2D-2phase numerical simulation on liquid water behavior in a straight channel PEFC, The 5th International Conference on Fuel Cell Science, Engineering and Technology, New York, NY, USA, June 18-20, 2007, 2007.06.
43. K. Sasaki, S. Adachi, K. Haga, M. Uchikawa, J. Yamamoto, A. Iyoshi, J.-T. Chou, and K. Itoh, Fuel Impurity Tolerance of Solid Oxide Fuel Cells, ECS Transactions, Vol.7, No.1, PP.1675-1683(2007), 2007.06.
44. Numerical Analysis of Transient Response in Polymer Electrolyte Membrane Fuel Cell Considering Gas/Liquid Two Phase Flow.
45. Kohei Ito, Hiromitsu Masuda, Tomohiko Miyazaki, Yasushi Kakimoto, Kensuke Ashikaga, Kazunari Sasaki, Numerical Simulation of Two-Phase Flow and Transient Response in Polymer Electrolyte Fuel Cell, The 4th International Conference on Fuel Cell Science, Engineering and Technology, Irvine, CA, USA, June 19-21, 2006, 2006.06.
46. Kohei Ito, Hiromitsu Masuda, Tomohiko Miyazaki, Yasushi Kakimoto, Kensuke Ashikaga, Kazunari Sasaki, Estimation of Flooding in PEMFC Gas Diffusion Layer by Differential Pressure Measurement, The 4th International Conference on Fuel Cell Science, Engineering and Technology, Irvine, CA, USA, June 19-21, 2006, 2006.06.
47. Local water-content measurement of polymer electrolyte membrane for fuel cell applications using planar surface coil as a NMR signal detector.
Presentations
1. Impact of bubble behavior on performance of PEM water electrolyzer.
2. Cold Start Characteristics of Polymer Electrolyte Fuel Cell.
3. A review and trial on pressurizing of electrochemical hydrogen pump .
4. Characterization of electrochemical hydrogen pump under high pressure condition.
5. A review and trial on pressurizing of electrochemical hydrogen pump .
6. A sectional observation and analysis of water droplet in the flow channel in PEFC.
7. A sectional observation and analysis of water droplet in the flow channel in PEFC.
8. A Development of 3D Temperature Measurement Technique
for Unit PEFC by Using In-Line Thermocouple and Supporter.
9. Water-behavior-triggered correlation between cell voltage and cathode differential pressure.
10. Measurement of Hydrogen-gas solubility in KOHaq up to 30MPa.
11. Measurement of Hydrogen Solubility and Diffusivity in Rubber by NMR method
.
12. In situ measurement of temperature distribution across a PEFC
.
13. Hydrogen solubility in water.
14. Flooding analysis by visualization cell with various flow-channel pattern.
15. A consideration of boundary condition for Boltzmann transport equation.
16. An observation of water behavior in PEFC in through-plane direction
by using a sectional model cell.
17. Impact of liquid-gas two phase flow on water electrolysis cell performance.
18. Numerical Analysis of Water Electrolysis Process under High-Pressure Condition considering Hydrogen and Oxygen Dissolution based on Vapor-Liquid Equilibrium
.
19. Experimental investigation of influence of two-phase flow behavior on PEEC performance
(using the cell without flow channel).
20. Measurement of temperature distribution across unit PEFC.
21. A measurement method for water droplets distribution based on distributed-type optical fiber technique
.
22. Effect of two-phase flow behavior on performance of Polymer Electrolyte Electrolysis Cell.
23. Numerical Analysis of Water Electrolysis Cell considering hydrogen and oxygen solubility.
24. Development of a diagnostic sensor for PEFC Water Problem.
25. Development of a measurement system for current and water-content with NMR sensor in polymer electrolyte membrane for fuel cell.
26. Analysis for entropy generation and temperature in through-plain direction of PEFC.
27. Development of real-time measurement of methanol-concentration in polymer electrolyte membrane using a local NMR sensor.
28. Distribution measurement of water content in PEM under water electrolysis condition using multi-NMR sensors.
29. Numerical analysis of Boltzman Transport Equation for heat and electric transport in metalic plate when a potential difference exists in through-plain direction.
30. Numerical Analysis of Water Electrolysis Cell considering hydrogen solubility.
31. Estimation of flooding in PEMFC gas diffusion layer by differential pressure measurement.
32. Calculation of entropy generation and measurement temperature profile in PEFC.
33. Calculation of entropy generation in PEFC.
34. Obserbation of flooding using a tranparent PEMFC and its influence on cell voltage.
35. Numerical analysis of thermoelectric phenomena by Boltzmann transport equation with discretization of every wave-number space.
36. Water-content measurement in PEM under water electrolysis condition using a local NMR sensor.
37. Estimate of flooding in fuel cell diffusion layer by differential pressure measurement.
38. Comparison between two-phase numerical analysis and visualization experiment of polymer electrolyte fuel cell.
39. Numerical Analysis of thermoelectricity in Metal Based on Boltzmann Transport Equation.
40. Development of a local NMR sensor for wetness monitoring of
polymer electrolyte membrane using a planar surface coil.
41. Two-phase flow Numerical Analysis for Transient Response of PEMFC.
42. Two-phase flow Phenomena under Transient State of PEMFC.
43. Investigation of Water Blocking Phenomena in PEMFC by Numerical Simulation.
Membership in Academic Society
  • Japan Journal of Thermophysical Properties
  • Electrochemical Society of Japan
  • Heat Transfer Society of Japan
  • Japan Society of Mechanical Engineering
Awards
  • Encouraging prize by W.J. Yang
Educational
Educational Activities
 I am charge of the classes in undergraduate course of mechanical engineering such as, thermal energy conversion. In addition, I educate systems and elements issues of hydrogen energy technology, such as fuel cell, through the lecture of hydrogen utilization system etc. I am assigned as supervisor for bachelor, master, and doctor course students.
Other Educational Activities
  • 2014.05, I educate safety issues to students and staffs. In addition, practical training are imposed to them, to get understandings of hydrogen gas properties and piping..
  • 2010.07.
  • 2009.04.
  • 2008.08.
  • 2004.05, "Manual of emergency in hydrogen experimental stand".