In-Situ Estimation of Faradaic Efficiency for a Direct Methanol Fuel Cell Stack by a Carbon Dioxide Saturated Solution Method

2009 ◽  
Author(s):  
Liang Qi ◽  
Xiaofeng Xie ◽  
Ibrahim Alaefour ◽  
Aaron Pereira ◽  
Xianguo Li
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Direct Methanol Fuel Cell ◽  
Solution Method ◽  
Air Flow ◽  
Saturated Solution ◽  
Air Flow Rate ◽  
Faradaic Efficiency ◽  
Direct Methanol ◽  
Methanol Fuel Cell

A direct methanol fuel cell (DMFC) system consisting of 40 single cells was assembled to study the influence of the transport phenomena at the anode and stack faradaic efficiencies by a CO2 saturated solution method. This method corrected the common experimental error in measuring methanol crossover caused by the simultaneous CO2 permeation from the anode to cathode. Both anode and stack faradaic efficiencies were estimated using this method. An equivalent “carbon-flow current” has been defined and a relationship between the transport phenomena and efficiencies was developed. Also the effect of methanol concentration, methanol flow rate and air flow rate on stack efficiency was studied. The results show that lower methanol flow rate, lower methanol concentration and higher air flow rate are all helpful in decreasing the methanol crossover and increase the stack faradaic efficiency.

Power Generation Experiment of Direct Methanol Fuel Cell

2011 ◽  
Vol 347-353 ◽  
pp. 3281-3285 ◽  
Author(s):  
Xin Zhou ◽  
Xiao Feng Xie ◽  
Motoo Ishikawa
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Direct Methanol Fuel Cell ◽  
Peak Power ◽  
Gas Flow ◽  
Operating Conditions ◽  
Air Flow Rate ◽  
Direct Methanol ◽  
Oxygen Gas ◽  
Methanol Fuel Cell

An experiment of a single direct methanol fuel cell (DMFC) was conducted at Fuel Cell laboratory of Tsinghua University, China in collaboration with University of Tsukuba, Japan. Influences of the anodic methanol solution's concentration, the cathodic air flow rate, and the cathodic oxygen gas flow rate on the single DMFC performance were investigated to optimize operating conditions of the fuel cell. The experimental results have shown that the single DMFC can reach the peak power density of 0.170 W/cm2 with the current of 0.515 A/cm2 under the condition of the concentration of methanol solution of 2M and the flow rate of oxygen gas of 80 mL/min.

Performance and Modeling of a Liquid-Fed Direct Methanol Fuel Cell

2004 ◽  
Author(s):  
Jiabin Ge ◽  
Hongtan Liu
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Direct Methanol Fuel Cell ◽  
Species Conservation ◽  
Three Dimensional ◽  
Electrochemical Kinetics ◽  
Operating Parameters ◽  
Liquid Feed ◽  
Direct Methanol ◽  
Methanol Fuel Cell

Systematic experiments have been conducted to study the effects of various operating parameters on the performance of a direct methanol fuel cell (DMFC). The effects of cell operating temperature, anode flow rate, air flow rate, and methanol concentration have been studied. The experimental results showed that the operating parameters have significant effects on the DMFC performances, and some of the effects are complicated and deserve further detailed studies. Selected results are presented in this paper. A three dimensional, single-phase, multi-component model has been developed for liquid-feed DMFC. The traditional continuity, momentum, and species conservation equations are used. At the anode, liquid phase is considered, and at the cathode, only gas phase is considered. In addition to the regular electrochemical kinetics at the anode and cathode, the mixed potential effects due to methanol crossover are also included in the model. The modeling results compared well with our experimental data.

Investigation of μDMFC (micro direct methanol fuel cell) with self-adaptive flow rate

Energy ◽  
2013 ◽  
Vol 55 ◽  
pp. 1152-1158 ◽  
Author(s):  
Zhenyu Yuan ◽  
Wenting Fu ◽  
Yang Zhao ◽  
Zipeng Li ◽  
Yufeng Zhang ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Direct Methanol Fuel Cell ◽  
Direct Methanol ◽  
Methanol Fuel Cell ◽  
Self Adaptive

Fabrication of a micro-direct methanol fuel cell using microfluidics

2012 ◽  
Vol 66 (12) ◽  
Author(s):  
Chumphol Yunphuttha ◽  
Win Bunjongpru ◽  
Supanit Porntheeraphat ◽  
Atchana Wongchaisuwat ◽  
Charndet Hruanun ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Direct Methanol Fuel Cell ◽  
Proton Exchange Membrane ◽  
Platinum Catalyst ◽  
Proton Exchange ◽  
Direct Methanol ◽  
Poly Ethylene ◽  
Exchange Membrane ◽  
Methanol Fuel Cell

AbstractA direct-methanol fuel cell containing three parts: microchannels, electrodes, and a proton exchange membrane (PEM), was investigated. Nafion resin (NR) and polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (PS) were used as PEMs. Preparation of PEMs, including compositing with other polymers and their solubility, was performed and their proton conductivity was measured by a four point probe. The results showed that the 5 % Nafion resin has lower conductivity than the 5 % PS solution. The micro-fuel cell contained two acrylic channels, PEM, and two platinum catalyst electrodes on a silicon wafer. The assembled micro-fuel cells used 2 M methanol at the flow rate of 1.5 mL min−1 in the anode channel and 5 × 10−3 M KMnO4 at the flow rate of 1.5 mL min−1 in the cathode channel. The micro-fuel cell with the electrode distance of 300 μm provided the power density of 59.16 μW cm−2 and the current density of 125.60 μA cm−2 at 0.47 V.

scholarly journals Effects of operating parameters on performance of a single direct methanol fuel cell

2010 ◽  
Vol 14 (2) ◽  
pp. 469-477 ◽  
Author(s):  
Ebrahim Alizadeh ◽  
Mousa Farhadi ◽  
Kurosh Sedighi ◽  
Mohsen Shakeri
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Direct Methanol Fuel Cell ◽  
Cell Voltage ◽  
Oxygen Flow Rate ◽  
Methanol Concentration ◽  
Cell Performance ◽  
Oxygen Flow ◽  
Direct Methanol ◽  
Methanol Fuel Cell

In this study the effect of various operating conditions on 10 cm ?10 cm active area of in-house fabricated direct methanol fuel cell was investigated experimentally. The effect of the cell temperature, methanol concentration, and oxygen flow rate on cell performance was studied. The study reveals that current density is not monotonous function of temperature, but has an optimum operating condition for each cell voltage. The experiments also indicate that the cell performance increases with an increased of oxygen flow rate up to a certain value and then further increase has no significant effect. Furthermore, for methanol concentration greater than 1.5 M, a reduction of cell voltage was indicated which is due to an increase of methanol cross over.

3D Numerical Study of a Flowing Electrolyte – Direct Methanol Fuel Cell With an Implemented Bi-Layered Membrane Electrode Diaphragm Assembly

2011 ◽  
Author(s):  
P. A. Cornellier ◽  
E. Matida ◽  
C. A. Cruickshank
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Direct Methanol Fuel Cell ◽  
Numerical Study ◽  
Experimental Studies ◽  
Membrane Electrode ◽  
Pressure Losses ◽  
Direct Methanol ◽  
Flow Through ◽  
Methanol Fuel Cell

In the present work, fluid dynamic simulation and experimental studies are compared to assess the validity of using computational fluid dynamics (CFD) to accurately predict the pressure losses experienced across each of the three fluid channels in a flowing electrolyte direct methanol fuel cell: methanol flow through anodic-serpentine channels; air flow through the cathodic-serpentine channels; dilute sulfuric acid flow through the flowing electrolyte (FE) channel located between two membrane-electrode assemblies (MEAs). The methanol flow rate is varied from 5 to 25 mL/min and the airflow is varied from 0.5 to 5 L/min. The flowing electrolyte flow rate is also varied from 5 to 25 mL/min in order to analyze pressure levels within the FE channel, which, according to this analysis, must be larger than the adjacent serpentine channels. This pressure difference is particularly important to maintain the distance (and flow structure) between the MEAs without affecting performance of the fuel cell. Adequately controlling the pressure of each of three fluids disables the MEAs ability to deform without the use of an electrolyte spacer, effectively creating an inter-dependent bi-layered membrane electrode diaphragm assembly (Bi-MEDA). Through CFD simulation, it was observed that pressure equalization through the Bi-MEDA approach supports the elimination of a flowing electrolyte channel spacer from current FE-DMFC designs. The reduction of the spacer is expected to decrease ohmic losses currently experienced in all FE-DMFC designs. Despite several approximations, simulations predicting pressure losses throughout the two serpentine fuel channels are compared against obtained experimental data, showing relatively good agreement for a single cell arrangement.

Experimental Analysis of a Small-Scale Flowing Electrolyte–Direct Methanol Fuel Cell Stack

2015 ◽  
Vol 12 (4) ◽  
Author(s):  
Yashar Kablou ◽  
Cynthia A. Cruickshank ◽  
Edgar Matida
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Power Output ◽  
Direct Methanol Fuel Cell ◽  
Operating Conditions ◽  
Solution Flow Rate ◽  
Small Scale ◽  
Solution Flow ◽  
Direct Methanol ◽  
Methanol Fuel Cell

A small-scale five-cell flowing electrolyte–direct methanol fuel cell (FE-DMFC) stack with U-type manifold configuration and parallel serpentine flow bed design was studied experimentally. The active area of a single cell was approximately 25 cm2. For every stack cell, diluted sulphuric acid was used as the flowing electrolyte (FE) which was circulated through a porous medium placed between two Nafion® 115 polymer electrolyte membranes. The stack performance was studied over a range of several operating conditions, such as temperature (50–80 °C), FE flow rate (0–17.5 ml/min), methanol concentration (0.5–4.0 M), and methanol solution flow rate (10–20 ml/min). In addition, the stack cell to cell voltage variations and the effects of the FE stream interruption on the output voltage were investigated at various operating loads. Experimental results showed that utilization of the FE effectively reduced methanol crossover and improved the stack power output. It was found that increasing the FE flow rate enhanced the stack capability to operate at higher inlet methanol concentrations without any degradation to the performance. The results also demonstrated that the stack power output can be directly controlled by regulating the FE stream especially at high operating currents.

Effects of Operating Conditions on Direct Methanol Fuel Cell Performance Using Nafion-Based Polymer Electrolytes

2014 ◽  
Vol 11 (6) ◽  
Author(s):  
Shingjiang Jessie Lue ◽  
Wei-Luen Hsu ◽  
Chen-Yu Chao ◽  
K. P. O. Mahesh
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Direct Methanol Fuel Cell ◽  
Methanol Solution ◽  
Operating Conditions ◽  
Methanol Concentration ◽  
Cell Performance ◽  
Stoichiometric Ratio ◽  
Direct Methanol ◽  
Methanol Fuel Cell

Systematic experiments were carried out to study the effects of various operating conditions on the performances of a direct methanol fuel cell (DMFC) using Nafion 117 and its modified membranes. The cell performance was studied as a function of cell operating temperature, methanol concentration, methanol flow rate, oxygen flow rate, and methanol-to-oxygen stoichiometric ratio. The experimental results revealed that the most significant factor was the temperature, increasing the cell performance from 50 to 80 °C. We achieved the maximum power density (Pmax) of 86.4 mW cm−2 for a DMFC at 80 °C fed with 1 M methanol (flow rate of 2 ml min−1) and humidified oxygen (80 ml min−1). A methanol concentration of 1 M gave much better performance than using 3 M of methanol solution. The oxygen and methanol flow rates with the same stoichiometric ratio had a beneficial effect on cell performance up to certain values, beyond which further increase in flow rate had limited effect. The Voc using argon plasma-modified Nafion was higher than the pristine Nafion membrane for the cell operated on 3 M methanol solution, which was due to the lower methanol permeability of the Ar-modified Nafion.

Dynamic Characteristics of a Direct Methanol Fuel Cell

2005 ◽  
Vol 3 (2) ◽  
pp. 202-207 ◽  
Author(s):  
Maohai Wang ◽  
Hang Guo ◽  
Chongfang Ma
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Dynamic Characteristics ◽  
Cell Response ◽  
Direct Methanol Fuel Cell ◽  
Oxygen Flow Rate ◽  
Oxygen Flow ◽  
Cell Temperature ◽  
Direct Methanol ◽  
Methanol Fuel Cell

The detailed dynamic characteristics of direct methanol fuel cells need to be known if they are used for transportable power sources. The dynamic response of a direct methanol fuel cell to variable loading conditions, the effect of cell temperature and oxygen flow rate on the cell response, and the cell response to continuously varying cell temperatures were examined experimentally. The results revealed that the cell responds rapidly to variable current cycles and to continuously varying cell temperatures. The increasing rate of gradual loading significantly influences the dynamic behavior. The effects of cell temperature and oxygen flow rate on the cell dynamic responses are considerable, but the cell voltage differences over the range of cell temperatures and oxygen flow rates are small for gradual loading. The cell response value to cell temperature during decreasing temperature is lower than that during increasing temperature.

Semi-Empirical Flow and Pressure Distribution Modeling of a Flowing Electrolyte Direct Methanol Fuel Cell Stack

2011 ◽  
Author(s):  
Yashar Kablou ◽  
Cynthia A. Cruickshank ◽  
David Ouellette ◽  
Edgar Matida
Keyword(s):  
Fuel Cell ◽  
Pressure Drop ◽  
Pressure Distribution ◽  
Flow Rate ◽  
Direct Methanol Fuel Cell ◽  
Hardy Cross ◽  
Direct Methanol ◽  
The Individual ◽  
Semi Empirical ◽  
Methanol Fuel Cell

The pressure distribution across a flowing electrolyte - direct methanol fuel cell (FE-DMFC) stack was numerically evaluated using semi-empirical equations for friction and loss coefficients. The stack is considered to have “U” shape manifold design with parallel serpentine fuel channels. The flow is assumed to be laminar and the flow rate in each cell of the stack is determined using the Hardy-Cross method. The results show that, the mass flow rate of methanol is greater at the inlet and declines as the fuel travels further within the stack manifolds. It was further discovered that pressure drop inside the inlet manifolds increases with stack length while the pressure drop inside the individual cell channels tend to decrease with stack length. Finally, the stack power output is estimated by assuming single cell power outputs at various operating current densities and methanol inlet flow rates based on experimental data obtained from the literature.

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