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Öğe A borohydride/peroxide fuel cell-Li-ion battery hybrid system controlled with a maximum peak power tracking algorithm(Pergamon-Elsevier Science Ltd, 2015) Yilmaz, Eyup; Canan, Belkis; Sanli, Ayse Elif; Mat, Mahmut D.; Gunlu, GokselThe present study was carried out to develop a direct borohydride/peroxide fuel cell (DBPFC)/Li-ion battery hybrid system. In the system, the battery was charged with DBPFC. The output power of the DBPFC was controlled by a MPPT algorithm. It consists of two main parts: a DC/DC converter and a DSP controller. TMS320F28027 DSP was used to manage the entire MPPT circuit. The DC/DC controller was placed between the fuel cell and the battery. The performance test results indicated that the output power remained constant at 1.3 W during the test. Moreover, the voltage ripples that are generally observed in the fuel cells were prevented. The fuel cell provided the power at the maximum peak power for approximately 211 min. It was obvious that the Li-Ion battery was charged with a stable DBPFC power. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Öğe A novel H2S/H2O2 fuel cell operating at the temperature of 298K(Wiley, 2013) Sanli, Ayse Elif; Yilmaz, Orhan; Aytac, AylinIn this study, the oxidation mechanism of hydrogen sulfide (H2S) is investigated, and a fuel cell operating with acidic peroxide as oxidant and basic hydrogen sulfide as fuel is constructed. A stable solid state H2S/H2O2 fuel cell has been developed at the temperature of 298K. A nickel anode catalyst has been examined using Nafion-117 as a proton-conducting membrane. In an operating with the acidic hydrogen peroxide (H2O2) as oxidant, the cell potential was increased to a value of 0.85V at 298K. The main conclusion of this study is the management to increase the cell potential to 850mV at 25 degrees C, whereas this value can only be achieved in the H2S/O-2 fuel cell at 850-1000 degrees C. Moreover, there exists no prior work on the H2S/H2O2 fuel cell research. Copyright (c) 2012 John Wiley & Sons, Ltd.Öğe A possible future fuel cell: the peroxide/peroxide fuel cell(Wiley, 2013) Sanli, Ayse ElifHydrogen peroxide (H2O2) and the reduction/oxidation by-products of peroxide are non-toxic to humans and the environment. Simple, low-concentration hydrogen-peroxide solutions used as fuel and direct peroxide/peroxide fuel cells (DPPFCs) face significant challenges in the development of a new class of power generators. A power density of 10 mWcm(-2) at a cell potential of 0.55V have been achieved with a DPPFC composed of carbon-paper-supported nickel as the anode catalyst and carbon-paper PbSO4 as the cathode catalyst. The catalysts have been prepared by electroless deposition. Using non-precious metals rather than platinum in our FC makes the cell cost effective comparable to that of PEMFCs. Additionally, as a low-price fuel, H2O2 reduces the cost of this FC. Copyright (c) 2012 John Wiley & Sons, Ltd.Öğe Comparison of Power and Energy Density after Full Shunting-Balancing in Serial Connected Lithium-ion Batteries and Serial-Connected Supercapacitors(Ieee, 2015) Sertkaya, Melek Gulatik; Yilmaz, Eyup; Sanli, Ayse Elif; Gunlu, GokselIn this study, advantages and disadvantages of supercapacitors and batteries which are energy storing sources were examined and furthermore, energy density, voltage and current behaviors of 6 serial connected supercapacitors and 6 serial connected battery sequences were compared. While establishing these circuits, full shunting balancing methods were used. When 4 units of 6 serial connected batteries/supercapacitors reached to the 100% charged level, system passed to discharging mode from charging mode and total charge ratios of the systems were calculated.Öğe Development a power management unit for small direct borohydride fuel cell - Li-ion battery hybrid system(2013) Sanli, Ayse Elif; Günlü, Göksel; Aytaç, AylinIn this study, a small portable borohydride fuel cell/Li-ion battery hybrid system has been developed. The system consists of a single portable direct borohydride/peroxide fuel cell (DBPFC), Li-ion battery and power management unit (PMU). The battery has been used as a primary power sources and discharged at constant load. When its state of charge has reduced, the DBPFC has charged the battery and has powered the load simultaneously. A DC-DC Boost converter has been used as a PMU. The DBPFC has generated the energy of 20.7 mWh while Li-ion battery has consumed the energy of 5.9 mWh. Total efficiency of the DBPFC-Li-ion battery hybrid system has been calculated as 28.5%. © The Electrochemical Society. © 2013 Elsevier B.V., All rights reserved.Öğe Development of a power management unit for small portable direct borohydride fuel cell-NiMH battery hybrid system(Pergamon-Elsevier Science Ltd, 2012) Sanli, Ayse Elif; Gunlu, Goksel; Aytac, Aylin; Mat, MahmutIn this study, a small portable fuel cell/battery hybrid system has been developed. The system consists of a single portable direct borohydride/peroxide fuel cell (DBPFC), NiMH battery and power management unit (PMU). The battery has been used as a primary power source and has been discharged at constant load. When its state of charge is reduced, the DBPFC charges the battery and powers the load simultaneously. A DC-DC Boost converter has been used as a PMU. The DBPFC has provided the total power of 0.21 Wh into the system during the charge. During this experimental study fuel (NaBH4) efficiency of 37% has been achieved in the hybrid system, while the system efficiency has been calculated as 34.5%. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Öğe Effects of power control techniques on hydrogen and oxygen evolution in direct borohydride peroxide fuel cells(Pergamon-Elsevier Science Ltd, 2017) Yilmaz, Eyup Semsi; Canan, Belkis; Gunlu, Goksel; Sanli, Ayse ElifDirect borohydride/peroxide fuel cells (DBPFCs) have some attractive features, such as high energy density, high theoretical cell power and low operational temperature. The drawbacks that cause performance loss include low efficiency and security challenges. Hydrogen and oxygen evolutions are major issues that should be considered when stacking a DBPFC. These gas evolutions significantly affect the DBPFC performance, efficiency and security. However, the gases were also produced in the case of an open circuit potential and depend on the applied voltage and current. Therefore, in the present study, the effects of cell loading on gas evolution were investigated. The DBPFC was operated under a constant voltage of 1.2 V and controlled using the maximum peak power tracking (MPPT) method. The MPPT control provided higher power generation and higher hydrogen evolution than observed using the constant voltage mode. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Öğe Electrochemistry of The Nickel Electrode as a Cathode Catalyst In The Media Of Acidic Peroxide For Application of The Peroxide Fuel Cell(Electrochemical Soc Inc, 2012) Sanli, Ayse Elif; Aytac, AylinHydrogen peroxide reduces on the nickel electrode surface in the acidic medium. On the nickel electrode the passive film layers such as NiS and NiOOH form in the peroxide free solution. However the nickel surface was activated with the addition of the peroxide. The cyclic voltammetry (CV) and impedance (EIS) studies verified the passivation and activation states in peroxide free acidic solution and the acidic peroxide solution. The electrochemical reactions of the sulphuric acid and peroxide at nickel electrode were electrochemically analyzed by cyclic voltammetry (CV) and impedance spectroscopy (EIS)Öğe Fuel Cell Powered Hybrid System Controlled by the Maximum Peak Power Tracking Technique(Ieee, 2015) Gordesel, Merve; Canan, Belkis; Gunlu, Goksel; Sanli, Ayse ElifIn the present study a borohydride/peroxide fuel cell/Li-ion battery hybrid system was developed. Output power of DBPFC was controlled and kept constant by MPPT algorithm. The voltage ripples of the fuel cell were prevented. Moreover, Li-ion battery was charged with a stable power of direct borohydride/peroxide fuel cell.Öğe Investigation of Hybrid Fuel Cell-Battery Systems(Electrochemical Soc Inc, 2015) Gunlu, Goksel; Aktepe, Alper; Canan, Belkis; Sanli, Ayse ElifHybrid electric vehicles (HEV) are considered as the alternative propulsion systems. In the hybrid systems electrical storage component is the key element. Because size and weight of the battery defines the cost and performance of the overall system. Another major component of a hybrid system is the fuel cell system consisted of a fuel cell stack, a membrane humidifier and hydrogen storage canisters. The power management system (PMS) is a critical component of hybrid electric vehicles. The purpose of the PMS is to maintain the safety and reliability of the battery, state monitoring and evaluation, charge control, and cell balancing. Three light electric vehicles (LEV) equipped a fuel cell-battery hybrid power system have reviewed in the present work. The hybrid power systems reviewed have consisted of a proton exchange membrane (PEM) fuel cell, a lithium battery and a power management unit. They are Buddy El-Jet Hybrid Vehicle from Toyota, Hydrogen-Electric Hybrid Microcab H2EV Vehicle tested at CABLED project in England and Norwegian Buddy El-Jet Hybrid System.Öğe Investigation of the electro-oxidation of artificial Black Sea water by cyclic voltammetry on molybdenum (II)(Pergamon-Elsevier Science Ltd, 2014) Sanli, Ayse Elif; Aytac, Aylin; Mat, MahmutThe electro-oxidation of H2S in Black Sea water to generate electricity was investigated. MoS2 exhibited catalytic activity toward the oxidation of H2S in artificial sea water. The catalytic activity of molybdenum sulfide was found to depend on the electrolyte pH and on the temperature. Cyclic voltammograms taken in the artificial sea water containing hydrogen sulfide at pH = 14 exhibited a peak at 500 mV related to the oxidation of HS-. Furthermore, the peak current of the MoS2 electrode increased to 400 mA g(-1) from 250 mA g(-1) (approximately 1.6-fold) when the temperature was increased from 353 K to 363 K. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Öğe Investigation of the electro-oxidation of artificial Black Sea water using cyclic voltammetry on metal sulfide electrodes (I)(Pergamon-Elsevier Science Ltd, 2014) Sanli, Ayse Elif; Yilmaz, Orhan; Aytac, Aylin; Mat, Mahmut D.Black Seawater is an alternative hydrogen source because it has hydrogen sulfide content. Seawater electrolysis is a promising method to produce hydrogen. The anodic oxidation of hydrogen sulfide is a novel approach for directly generating electricity via fuel cells. Therefore, four materials (Cu, Stainless Steel 304 (SS), V2O5 and Ni) were examined in artificial seawater containing hydrogen sulfide (HS-). We developed active metal sulfide electrodes for oxidizing HS-. Alongside the corrosion potentials, the progression of the oxidation and reduction reactions was obtained by the cyclic voltammetry method. The active behaviors of the metal sulfide (MSx) layers were determined by applying Electrochemical Impedance Spectroscopy (EIS). Although the Cu2S electrode acts as the active catalyst during HS- ion oxidation, NiS is the most suitable metal sulfide because it exhibits a higher corrosion resistance than Cu2S. While V2O5 demonstrates catalytic activity at high temperatures (>= 30 degrees C), FeS layers corrode easily in the artificial seawater environment. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Öğe Investigation of the vehicle application of fuel cell-battery hybrid systems(Springer International Publishing, 2016) Sanli, Ayse Elif; Günlü, GökselAll electric vehicles (AEV) are developed using the new technology; they can be separated in two groups as battery-operated electric vehicles (EV) and fuel cell vehicles (FCV). The subject of this study, fuel cell-battery operated hybrid vehicles, is about full electric hybrid vehicles (FEHV). EV and FCV have different advantages and disadvantages, therefore it is necessary to develop the FEHV vehicles. The fuel cell-battery hybrid systems are under investigation. In the literature, some automotive applications are reported as examples for fuel cell-battery hybrid powered systems. The light hybrid vehicles have been tested in terms of the system design, power management, road tests, and efficiency. All of the presented systems consist of a proton exchange membrane fuel cell system, battery pack, powertrain system, and a connection strategy for powering the traction of an electrical car. However, these are not perfect vehicles, they require further work to address major drawbacks with the connection as well, to increase the efficiency and management of the hybrid components (fuel cell, battery, supercapacitors, motor drive, and electrical systems), motor drive and electrical systems. Their tests and the demonstration results are satisfactory. © 2017 Elsevier B.V., All rights reserved.Öğe Performance analysis of direct Black Sea hydrogen sulphide (in artificial sea water)/hydrogen peroxide fuel cells(Pergamon-Elsevier Science Ltd, 2015) Sanli, Ayse Elif; Mat, Mahmut D.This study aims to analyse fuel cells constructed with the artificial Black Sea water containing hydrogen sulphide (H2S) as fuel. A parametric analysis of the performance of the direct H2S/H2O2 fuel cells is conducted to investigate the effect of certain parameters on the cells operation. The effects of the concentration of anolyte and catholyte and the pH of the anolyte are investigated. Increasing the solution pH leads to increased HS- concentration of the anolyte, resulting in higher cell power. The concentration of H2O2 has a greater impact on the cell's power density than the other parameters investigated. In the present study, the fuel cell can yield a power density of 23 mW cm(-2) at a cell voltage of 300 mV and current density of 75 mA cm(-2). Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Öğe Performance improvement in direct borohydride/peroxide fuel cells(Pergamon-Elsevier Science Ltd, 2017) Sanli, Ayse Elif; Gordesel, Merve; Yilmaz, Eyup Semsi; Ozden, Suleyman Kursat; Gunlu, Goksel; Uysal, Bekir ZuhtuDirect borohydride/peroxide fuel cells (DBPFCs) show progressively deteriorating performance during operation for various reasons such as decreasing reactant concentrations, gas evolution and uneven distribution of liquids. The present study aims to emphasize the importance of certain design parameters, such as bipolar plate materials, flow fields and manifold design, in determining the DBPFC performance. Bipolar materials and flow channel design have been investigated. A power density of 67 mW cm(-2) has been obtained with composite graphite and parallel flow channel bipolar plates. It has increased to 87 mW cm(-2) using sintered graphite and then to 93.3 mW cm(-2) using sintered graphite with serpentine flow fields. The stacking of DBPFCs results in a loss of performance and unstable output. The performance has remained nearly unchanged as the cell number was increased by applying an independent cell liquid distribution network (ICLDN). Using an ICLDN, power densities of 98.3, 83.3 and 82 mW cm(-2) have been obtained for single-cell, 3-cell and 6-cell stacks, respectively. Finally, a controlled oxidant feeding system (COFS) has been developed to provide stable output power, and it has demonstrated a stable output power of 6 W for 2.5 h. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Öğe The Multi-Windings Forward Structure Battery Balancing(Ieee, 2014) Gerislioglu, Burak; Ozturk, Furkan; Sanli, Ayse Elif; Gunlu, GokselA structure for active battery balancing with using Multi-Windings Transformer is presented. Most of applications in electrical vehicles need smart voltage control and high effective battery systems. In generally, the battery stack systems consist of these three parts: management, safety and balancing. In these parts, balancing is the most significant part since the management demands to improve the cycle life, battery storage packs, and power capacity. This paper presents the real-time Multi-Windings Transformer balancing topology forward structure model, simulation, and real circuit implementation with using Texas Instruments Stellaris (R) Launchpad Evaluation Kit (EK-LM4F120XL) with Energia based coding. Also, this paper indicates the emphasis of using forward structure model of Multi-Windings Transformer balancing topology since we use forward structure converter for dimishing the extra energy loses and decrease cost of the system.Öğe Use of the Blacksea Water Containing Hydrogen Sulfide (H2s) as a Fuel Cell Fuel(Electrochemical Soc Inc, 2015) Sanli, Ayse Elif; Canan, Belkis; Aytac, AylinBlack Seawater is a hydrogen source because of high hydrogen sulfide (H2S) content. H2S is the chemical electron donor. Energy can be generated from H2S by the oxidation or by the electrooxidation. Electrochemical systems such as fuel cells are the powerful alternative to recovery of sulfur and to generate energy. In the present study Black seawater with H2S content has been investigated as a fuel cell fuel. The electrochemical behaviors of metal sulfides have been performed in the solution containing H2S. NiS has showed the catalytic effect towards the electro- oxidation of HS- ions. A fuel cell constructed with Ni anode and Pt cathode has provided the maximum power density of 23 mWcm(-2) at the potential of 300 mV and 75 mAcm(-2).
