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.

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.

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.

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.

scholarly journals Optimum Conditions for Maximum Power of a Direct Methanol Fuel Cell

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mojtaba Tafaoli-Masoule ◽  
Arian Bahrami ◽  
Danial Mohammadrezaei
Keyword(s):  
Fuel Cell ◽  
Direct Methanol Fuel Cell ◽  
Operating Conditions ◽  
Maximum Power ◽  
Effective Parameters ◽  
Cell Temperature ◽  
Isothermal Model ◽  
Direct Methanol ◽  
Methanol Fuel Cell ◽  
Good Agreement

It is well known that anode and cathode pressures and cell temperature are the effective parameters in performance of Direct Methanol Fuel Cell (DMFC). In the present study, the genetic algorithm as one of the most powerful optimization tools is applied to determine operating conditions which result in the maximum power density of a DMFC. A quasi-two-dimensional, isothermal model is presented to determine maximum power of a DMFC. For validation of this model, the results of the model are compared to experimental results and shown to be in good agreement with them.

The Effect of Cell Temperature and Channel Geometry on the Performance of a Direct Methanol Fuel Cell

2011 ◽  
Vol 8 (6) ◽  
Author(s):  
Mojtaba Parvizi Omran ◽  
Mousa Farhadi ◽  
Kurosh Sedighi
Keyword(s):  
Fuel Cell ◽  
Power Density ◽  
Direct Methanol Fuel Cell ◽  
Species Conservation ◽  
Channel Width ◽  
Limiting Current ◽  
Electrochemical Kinetics ◽  
Cell Temperature ◽  
Direct Methanol ◽  
Methanol Fuel Cell

A 3D, single phase steady-state model has been developed for liquid feed direct methanol fuel cell. The model is implemented into the commercial computational fluid dynamics (CFD) software package FLUENT® v6.2, with its user-defined functions (UDFs). The continuity, momentum, and species conservation equations are coupled with electrochemical kinetics in the anode and cathode channel and MEA. For electro chemical kinetics, the Tafel equation is used at both the anode and cathode sides. Results are validated against DMFC experimental data with reasonable agreement and used to study the effects of cell temperature, channel depth, and channel width on polarization curve, power density and crossover rate. The results show that the increasing operational temperature, the limiting current density and peak of power density increase and subsequently crossover increases too. It is also shown that the increasing of channel width is a beneficial way for improving cell performance at a methanol concentration below 1 M.

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

Systematic Experimental Analysis of a Direct Methanol Fuel Cell

2006 ◽  
Vol 4 (4) ◽  
pp. 418-424 ◽  
Author(s):  
A. Casalegno ◽  
R. Marchesi ◽  
F. Rinaldi
Keyword(s):  
Fuel Cell ◽  
Direct Methanol Fuel Cell ◽  
Operating Conditions ◽  
Experimental Results ◽  
Cell Temperature ◽  
Systematic Analysis ◽  
Operating Condition ◽  
Direct Methanol ◽  
Methanol Fuel Cell

Different studies are carried out to compare the performances of different fuel cell constructive materials and operating conditions. In this work, a methodology for the characterization of DMFC experimental results in term of uncertainty and repeatability and for a systematic analysis of operating condition influence on performance is presented. The measurement system (composed of calibrated instruments) and experimental and data elaboration procedures are described. Experimental results, characterized by uncertainty and repeatability, are discussed for different operating conditions: fuel cell temperature, anode flow rate, and methanol concentration. The influence of operating condition history on performance is observed. It arises also from accumulation, both of methanol and carbon dioxide at the anode side; consequently, the operating condition history has to be considered in evaluating direct methanol fuel cell (DMFC) performances and repeatability of measurements. This work confirms that to compare experimental performances of fuel cells, the measurements shall be characterized by traceability, repeatability, reproducibility, and uncertainty.

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.

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.

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