Diaphragm electrode unit for PEM fuel cell

Diaphragm electrode unit for PEM fuel cell

PATENTS Diaphragm electrode unit for PEM fuel cell Applicant: Siemens AG, Germany The invention covers a membrane electrode unit for a protonexchange ...

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PATENTS Diaphragm electrode unit for PEM fuel cell Applicant: Siemens AG, Germany The invention covers a membrane electrode unit for a protonexchange membrane (PEM) fuel cell, where the active electrode catalyst layer is directly pressed onto the diaphragm in the form of a dry powder. It also relates to a low-cost mass-production method for the diaphragm electrode unit, where the dry catalyst powder is applied to the diaphragm strip using a sieve and then processed without an additive using a press to form the electrode catalyst layer. Patent number." WO 00/26982 Inventors: K. Dennerlein, U. Gebhardt Publication date." 1 l May 2000

Planar fuel cell Applicant: Motorola Inc, USA This patent describes a planar fuel cell as well as a membrane-electrode assembly (MEA) which is sandwiched between two current collector assemblies. The MEA is a single sheet of polymer electrolyte membrane with an array of anodes on one side and an array of cathodes on the other side. Current collectors can be supported by a plastic frame, and have an interconnect tab which provides an electrical pathway to the exterior of the MEA. The interconnect tab~s situated so that it provides electron transfer between the anodes and cathodes, and so that it does not traverse the thickness of the polymer electrolyte membrane. When the planar fuel cell is assembled, the interconnect tab is sealed to prevent leaking of fuel or oxidant gases. Fuel is distributed to only one side of the MEA while oxidant is distributed only to the other side. Patent number: WO 00/26980 Inw'ntors: S. Pratt, R.J. Kelley, S. Muthuswam> B. Landreth, R.W. Pennisi Publication date: 11.May 2000

Fuel system for fuel cell Applicant: Forschungszentrum Jiilich, Germany The invention relates to a method for adjusting the concentration of a fuel mixture for a fuel cell, which uses alcohol or ether. Such fuel cells are operated using a fuel/water mixture in which the fuel usually has a concentration of 1-5 vol%.

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The aim is to provide a fuel concentration which is as constant as possible. However, for the abovementioned concentration range, a sufficiently exact and/or fast method for directly measuring the fuel concentration has not been known. In this invention, the fuel concentration is adjusted to a constant value by means of a specific probe. This has a measuring chamber and a membrane which closes the measuring chamber. Fuel and water permeate the membrane, which is selectively permeable in such a way that a measuring mixture is formed in the measuring chamber. In this chamber the alcohol concentration is less than 1 vol% or more than 5 vol%. Suitable fuel sensors can be used for a range of concentrations. Patent number." WO 00/26978 Inventors: D. Meissner, H.-E Oetjen, J. Mergel Publication date: 11 May 2000

Membrane-electrode assembly for PEM fuel cell Applicants: International Fuel Cells, USA An improved membrane-electrode assembly for proton-exchange membrane (PEM) tirol cells is the subject of this patent. Gas diffusion layers are disposed on the cell's catalyst layers. Porous substrates are disposed respectively on the gas diffusion layers, but these are not placed in contact with the catalyst layers. The porous substrates are impregnated at their periphery with a sealant in the regions which are in contact with the porous substrates. The gas diffusion layers, porous substrates and catalyst layers are coextensive with the PEM. Patent number: WO 00/26975 Inventor: M. Krasij, R.D. Breauh Publication date: 11 May 2000

Enhanced membrane electrode device Applicant: PTI Advanced Filtration Inc, USA Here one electrode is provided in association with the object to be coated - - the other electrode. A prestretched ion-exchange membrane in thin, tubular form is sandwiched in between two non-conductive, water-permeable screen tubular housings. The assembly contains a supply line which provides a "waterway" through which an electrolyte flows. The flow" is from

the top of the device into a lower cap, and then on to the lower cap reservoir. This allows stabitisation and disbursement of electrolyte through the rimed housing. Inertia developed through this defined pattern creates a swirling action that scrubs away the impurities from the anode. The supply line is located just inside the inner screen, which is inserted through both the upper housing and lower cap. The tubular electrode is situated on the inside of the membrane housing, completing the inner portion of the "waterway" return chamber. Patent number: W O 00/26445 Inventor." C.H. Lee Publication date: 11 May 2000

Membrane electrolytic cell Applicants: Bayer AG, Germany,

and De Nora SpA, Italy This electrochemical half-cell consists of at least one membrane, an electrode which functions as anode or cathode that optionally produces gas, an outlet for the gas, and a support structure which links the gas-producing electrode with the back wall of the half-cell. The support structure divides the interior of the half-cell into vertically arranged channels. The electrolyte flows upwards in the electrode channels facing the electrode, and flows downwards in the channels facing away from the electrode. The electrode channels, and the channels facing away from the electrode, are interlinked at their upper and lower ends. Patent number: W O 00/26442 Inventors.. E Gestermann, E Fabian Publication date: 11 May 2000

Nitrate-free recycling Applicant: Eilenburger Elektrolyseund Umwelttechnik GmbH, Germany So far, pickling methods for special steels have either been linked with ecological hazards or they have not permitted the recycling of the pickling chemicals or the regeneration of the pickling solution and the simultaneous conversion of the dissolved metals into reusable form. The "recycling pickling method" described here uses a pickling solution which contains 1-6 mol/l of the dissolved metals in the form of sulfates, 0.3-3 mol/l sulfuric acid, and 0.1-5 moi/l of hydrofluoric acid. A characteristic feature of the method

is that part of the spent pickling solution circulates in a circuit between the pickling bath and the anode chambers of at least one recycling electrolytic cell, which is divided by an ion-exchange membrane. The partial flow is oxidised by anodic oxidation from a lower oxidation degree of a redox potential of 300-800 mV. This is adjusted in the pickling plant and measured against an Ag/AgCl reference electrode to a higher oxidation degree, with a redox potential of 600-1150 inV. Another partial flow of the spent pickling solution is guided through the cathode chambers, and optionally through additional 'intermediate chambers, and is removed from the cycle. The pickling method is used to remove oxide films on semi-finished and finished stainless-steel products. Patent number: W O 00/26441 Inventors: W. Thiele, K .Wildner Publication date: 11 May 2000

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