Papers by Keyword: PEMFC

Abstract: In order to improve the anti-corrosion characteristic of Ag-coated 316SS bipolar plates in PEMFC environment, self-assembled monolayer (SAM) was prepared on its surface by chemical methods. The electrochemical characteristic of modified bipolar plate was also investigated. The results indicated that the SAM was composed of dodecyl thioalcohol. After forming SAM, the bipolar plate’s contact angle increased from 58° to 102°. In addition, its double layer capacitance (Cd) was decreased and charge transfer resistance was increased. The homogeneous SAM, which acted as a protective barrier, inhibited the corrosive ion from corroding. SAM may provide significant protection against corrosion in PEMFC environment.

Abstract: Proton Exchange Membrane Fuel Cell (PEMFC) is established for the numerical simulation computation by using the MATLAB/SIMULINK, By changing the different working conditions, The proton exchange membrane fuel cell output performance is analyzed .Data show that the hydrogen pressure, oxygen pressure, current density, temperature, has certain influence on voltage and power distribution of PEMFC, For PEMFC to normal and stable work, according to the above conditions should be obtained the optimal value, thus ensuring optimal output performance of PEMFC.

Abstract: A hybrid mobile power supply is developed based on air-cooled Proton Exchange Membrane Fuel Cell (PEMFC) and lithium battery. Pure fuel cell provides a rated output of 25W. With the assistance of lithium battery, the system provides instantaneous power of 50W. The system consists of fuel cell and its controller, lithium battery and its management circuit, power switching circuit, system control circuit and DC/DC convert circuit. The system is designed and realized, the measurement results show that the system works steadily below 50W.

Abstract: PANI coating was electrochemically synthesized by cyclic voltammetry (CV) method on the surface of 316L stainless steel plate. The surface morphology of PANI coating was observed by scanning electron microscopy. The effect of oxygen gas on corrosion behavior of PANI coating in PEMFC environment was investigated. The corrosion performance of the coating was evaluated by potential-time curve and polarization curve as well as electrochemical impedance spectroscopy in a bath containing 1M H₂SO₄ and 2ppM NaF, and the air with a flow rate of 10 ml/min was piped into the testing corrosion cell to simulate the positive cathode condition of PEMFC at 70°C. The potential-time curves illustrated that oxygen gas resulted in the potential decline towards negative direction. Polarization curves showed that corrosion potential of the sample with O₂ was lower than that of the sample without O₂, and the corrosion current density was higher than that of the sample without O₂. EIS results indicated that the Nyquist plots were constitute of a capacitive impedance arc and a incline line, and the oxygen gas reduced the anti-corrosion performance of the PANI coating.

Abstract: Polyaniline (PANI) polymer coating was electrochemically synthetised by cyclic voltammetry (CV) method on stainless steel bipolar plates of proton exchange membrane fuel cell (PEMFC). Structure and morphology of PANI polymer coating were characterized by means of fourier transform infrared reflection (FTIR) spectrum and scanning electron microscopy (SEM). The corrosion behavior of the coating was evaluated by polarization curve and electrochemical impedance spectroscopy (EIS) in the medium of 1M H₂SO₄ and 2ppM NaF at 70°C to simulate the corrosive condition of PEMFC. It was found that the optimal conditions for PANI polymer coating synthesis could be 10-15 circles when the voltage ranged from-1.2V to +1.2V(Vs.SCE) with a scan rate of 50 mV/s. SEM observation results indicated that the polymer coating presented with uniform and dense feature. FTIR results illustrated that the coating were composed of PANI. Corrosion current densities of 316L SS and PANI-coated steel were 10^-5 and 10^-6 A/cm² respectively. Corrosion potential of the coated SS shifted towards more positive values compared to the uncoated plate. EIS results indicated that the radius of the capacity impedance for PANI increased obviously.

Abstract: Polymer Electrolyte Membrane Fuel Cell (PEMFC) is an alternative energy system that has been verified with great potential for high power density, durability and cost effectiveness. Since the bipolar plate is the key component in PEMFC, the component must operate with multifunction and have a balance of properties, essentially well in both electrical and mechanical properties. At present, many different materials have been tested to be applied for bipolar plate in order to fulfill the balance in each property. In this work, the different material is tested and observed. Polypropylene (PP) is used as a binder material, Graphite (Gr) is used as a main filler and Carbon Black (CB), Iron (Fe) and Nickel (Ni) as the second filler. This composite is produced through compression molding and the effect of different filler material loading on the properties such as electrical conductivity, flexural strength, bulk density and shore hardness are observed. The result showed the increasing of electrical conductivity as the increased the CB and Fe loading. But for Ni, the result showed the decreasing of electrical conductivity as the loading of Ni has been increased. The targeted value also achieved for some certain degree of filler loading.

Abstract: For the problems of different parameters PEMFC (Proton Exchange Membrane Fuel Cell) applied to dc micro-grid at the same time, the basic framework of two parallel PEMFC dc power supply system was put forward in this paper, meanwhile, the characteristics of this system was analyzed. For the problem of branch current distribution of parallel system, this paper set up the small signal mathematical model of BUCK connected in parallel, designed the control circuit of current-sharing of this system. Finally ,the simulation experiments verified the accuracy and rapidity of current sharing and the reliability and stability of this system, when the sub-circuit was fault.

Abstract: Nanofluid is an emerging technology in heat transfer study. The effect of nanofluids as a cooling medium in Proton Exchange Membrane Fuel Cell (PEMFC) is studied. Nanofluids with 0.1% and 0.5% of Al2O3 dispersed in base fluid of 50:50 mixture of Ethylene Glycol and water were analyzed experimentally. A 400 W liquid cooled PEMFC was used to verify the findings. The result showed that insignificant improvement in performance of PEMFC with nanofluids, perhaps due to the lower wattage of PEMFC used. However, the thermal performance is improved through the heat transfer rate increment of 68.5 % and 46 % for both 0.5 % of Al₂O₃ nanofluid and 0.1 % of Al₂O₃ nanofluid respectively.

Abstract: The cooling of proton exchange membranes fuel cell (PEMFC) is one of the crucial components in the heat management of a fuel cell. This paper presents three cooling channels of PEMFC: linear, serpentine and heat pipe. The cooling geometric models are proposed for the three cooling channels, respectively, and the corresponding temperature distributed diagrams are derived under steady state by SINDA/FLUINT. From the simulation, the linear cooling channel of PEMFC renders local overheating inside the cell under the same conditions, obviously. It is also observed that the serpentine cooling channel ensures the uniformity of cell temperature, whereas the change of channel diameter is not able to adjust the radiating performance effectively. Extensive simulation results show that the heat pipe cooling channel not only outperforms the other cooling channels in radiating performance, but also provides a remarkable environmental factor.

Abstract: PANI conducting polymer coating was electrochemically deposited on 316L stainless steel bipolar plates of PEMFC in the bath of 0.5M H2SO4 and 0.5M aniline. PANI coating could be synthesized with optimal conditions presenting in smooth and dense feature when the voltage was from 0.75V to 0.85V(Vs.SCE). The anti-corrosion performance of the coating was evaluated by electrochemical technique in the medium of 1M H2SO4 and 2ppM NaF at 70°C to simulate the working environment of PEMFC. It was found that the anodic branch of polarization curves presented in passivation character. EIS results indicated that the radius of the capacity impedance for PANI coating increased distinctly, which validated the excellent corrosion resistance of the coating. The surface morphology of the coating was observed by SEM, and the results showed that the surface of 316L stainless steel bipolar plates was covered by claviform shape coating. The chemical composition of the coating was investigated by FTIR and the results illustrated that the coating were composed of PANI.