Fuel cells polymer components

Stack Components In collaboration with partners, research and develop technologies to overcome the most critical technical hurdles for polymer electrolyte fuel cell stack components for both stationary and transportation applications. Critical technical hurdles include cost, durability, efficiency, and overall performance of components such as the proton exchange membranes, oxygen reduction electrodes, advanced catalysts, bipolar plates, etc. 

Polymer electrolyte fuel cell (PEFC) components generally have to fulfill the following four technical requirements to allow for an effective long-term fuel cell operation functionality, which is mostly determined by the product design service life which is influenced by the material as well as the design reliability, essentially determined by the manageability and process stability and sustainability, which is predominantly influenced by function integration and series production. 

Giilzow, E., Schulze, M., Wagner, N., Kaz, T., Reissner, R., Steinhilber, G., and Schneider, A. Dry layer preparation and characterization of polymer electrolyte fuel cell components. Journal of Power Sources 2000 86 352-362. 

Because of its lower temperature and special polymer electrolyte membrane, the proton exchange membrane fuel cell (PEMFC) is well-suited for transportation, portable, and micro fuel cell applications. But the performance of these fuel cells critically depends on the materials used for the various cell components. Durability, water management, and reducing catalyst poisoning are important factors when selecting PEMFC materials. 

The realization of the MEA is a crucial point for constructing a good fuel cell stack. The method currently used consists in hot-pressing (at 130 °C and 35 kg cm ) the electrode structures on the polymer membrane (Nafion). This gives non-reproducible results (in terms of interface resistance) and this is difficult to industrialize. New concepts must be elaborated, such as the continuous assembly of the three elements in a rolling tape process (as in the magnetic tape industry) or successive deposition of the component layers (microelectronic process) and so on. 

The first key component of a membrane fuel cell is the membrane electrolyte. Its central role lies in the separation of the two electrodes and the transport of ionic species (e.g. hydroxyl ion, OH , in an AEM), between them. In general, quaternary ammonium groups are used as anion-exchange groups in these materials. However, due to their low stability in highly alkaline media [43,44], only a few membranes have been evaluated for use as solid polymer electrolytes in alkaline fuel cells. 

One of the technically and commercially most important cation-exchange membranes developed in recent years is based on perfluorocarbon polymers. Membranes of this type have extreme chemical and thermal stability and they are the key component in the chlorine-alkaline electrolysis as well as in most of today s fuel cells. They are prepared by copolymerization of tetrafluoroethylene with perfluorovinylether having a carboxylic or sulfonic acid group at the end of a side chain. There are several variations of a general basic structure commercially available today [11]. The various preparation techniques are described in detail in the patent literature. 

The solid polymer electrolyte fuel cell is that on which the most development work was done in the 1990s because of its projected use in the development of an electrochemical engine for cars. The absence of a bulk liquid component while keeping to temperatures of 80 °C if pure H2 or H2 produced from methanol or gasoline on board a vehicle is available, signifies a great advantage. Conversely, the acid environment needs Pt. 

Fuel cells are the primary technology that will advance hydrogen use (DOE, 1998). Fuel cells are important as they are one component of a system that can efficiently produce electricity for many applications (Jacoby, 1999). It is also widely accepted that fuel cells are environmentally friendly (Hirschenhofer, 1997). Low temperature fuel cells, such as polymer-electrolyte-membrane (PEM) fuel cells, are being considered for many applications including electric power generation in commercial and residential buildings, automobile applications and... 

It is expected that the intermacromolecular complexes display entirely new physical and chemical characteristics different from those of the individual polymer components. So the following applications are, for example, considered membranes for dialysis, ultrafiltration, fuel cells and battery separators, wearing apparel, electrically conductive and antistatic coatings for textiles, medical and surgical prosthetic materials, environmental sensors or chemical detectors, and electrodes modified with specific polymers. 

The internal resistance of a fuel cell includes the electric contact resistance among the fuel cell components, and the proton resistance of the proton-conducting membrane. In PEMFCs, the proton resistance of the polymer electrolyte membrane contributes the most to the total ohmic resistance. 

The 3,4,5,6,7,8-hexahydro-l,2-oxathiocin 2,2-dioxide is the key component for the synthesis of a polymer used for proton exchange membrane fuel cells (PEMFCs). Membranes made with this polymer are pliant, do not expand much during wet conditions, and are chemically, hydrolytically, and thermally stable <2006USP0135702>. 

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