Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2008
Student: OĞUZHAN AKINÇ
Supervisor: NURSEL DİLSİZ
Abstract:In the scope of new energy technologies, fuel cells draw attention due to their many useful features. Fuel cells could be grouped under several titles according to their fuel and oxidizer composition, feeding the fuel directly or indirectly, type of electrode and operating temperature. In these different groups, Proton Exchange Membrane Fuel Cells (PEMFC) are the one in the lead that have many studies are being made on them today and that is believed to have many usage areas in the future, due to its simple structure, high efficiency and environment friendly operating features. Bipolar plates are the key component of proton exchange membrane fuel cells with multifunctional characters. They distribute fuel gas and air uniformly, conduct electrical current from cell to cell, removal of the heat from the active area and prevent leakage of gases. Bipolar plates have also significant effect on volume, weight, performance and cost of the fuel cell. Due to these significant effects, a huge research is going on the worldwide in order to determine the suitable materials to produce bipolar plates. The aim of this study is to prepare light composite bipolar plates fort he PEM Fuel Cells that has high mechanical strength and thermal durability. Graphite is added to the polypropylene to prepare bipolar plate in 10%, 15%, 20%, 25% and 30% ratios in this study. The highest electrical conductivity value is achieved with the 30% graphite added composite sample. 0,5% carbon nano fiber (CNF) is added in addition to 20% graphite added sample, which has the best results according to the thermal and mechanic tests related to the other samples. 20% graphite added sample's, which has no CNF, electrical conductivity is 141,60 (ohm.cm)-1 and then CNF is added to this sample in 0,5% and the electrical conductivity had increased to 192,10 (ohm.cm)-1. 20% graphite added sample has the highest tensile strength related to the other graphite added samples with 30,18 MPa. 0,5% CNF addition has lowered the tensile strength to 22,99 MPa, but the amount of strain has increased. When all the SEM micrographs and thermogravimetric analiysis of the samples are taken into account 20% graphite added sample has the best mechanical and thermal durability related to the other samples. CNF addition has an influence on electrical conductivity.