The invention relates to a method for operating a fuel cell system, in which method a supply of air to a fuel cell stack (20) is interrupted intermittently, in particular in the event of a standstill of the system, by means of a pressure-controlled shutoff valve (1), which comprises a valve element (4), which valve element can be moved back and forth between two end positions and is preloaded toward a sealing seat (3) by means of the spring force of a closing spring (2). According to the invention, in at least one of the two end positions, the valve element is held in the end position in question additionally by means of the magnetic force of an electromagnet (5) and/or of a permanent magnet (6), the electromagnet (5) and/or the permanent magnet (6) interacting with a magnetic or magnetizable part (7) of the valve element (4). The invention further relates to a shutoff valve (1) suitable for carrying out the method according to the invention and to a fuel cell stack (20) having at least one shutoff valve (1) according to the invention.

A fuel cell stack has a plurality of fuel cells arranged in a row, each of them comprising a membrane separating the electrodes, with ports for the respective supply and drainage of a fuel and an oxidizer and with a tensioning device for pressing the fuel cells together, wherein the tensioning device is formed by a band and spring system having an integrated force transducer, the signal of which can be relayed to a controller for determining the moisture content based on the moisture-dependent swelling behavior of the membrane of each fuel cell. A fuel cell device with such a fuel cell stack as well as a motor vehicle having such a fuel cell device are also provided.

Provided are an insulation detection method and apparatus for a fuel cell vehicle, and a vehicle. The method comprises: determining whether a vehicle is started; when the vehicle is started, executing the following steps: controlling a battery management system to perform the first insulation detection; detecting whether a fuel cell is started; and when the fuel cell is not started, controlling a fuel cell control unit to perform second insulation detection, wherein an insulation detection module for performing insulation detection on the fuel cell is provided in the fuel cell control unit of the vehicle.

The present invention relates to a protective reformer device (10) for the protection of an anode section (112) of a fuel cell stack (110) against oxidizing damage during a heating-up process, having a gas duct (20) with a gas inlet (22) and a gas outlet (24) for conducting fuel gas from an anode feed section (120) of the fuel cell stack (110), wherein a catalytic converter section (30) is arranged in the gas duct (20) for a catalytic oxidation of at least part of the fuel gas into a protective gas for feeding to the anode section (112), wherein, furthermore, the gas duct (20) has a temperature control device (40) in thermally transmitting contact with the catalytic converter section (30) for an active temperature control of the catalytic converter section (30).

Anion-exchange membranes are useful for electro-membrane processes such as electrodialysis (water desalination, separation of inorganics from organic molecules, separation of specific inorganic ion, etc.), in-situ ion-exchange and ion substitution, electro-deionization for producing ultrapure water, polymer electrolyte membrane for alkaline fuel cell and electrolysis applications. The present invention discloses an acid and base resistant fluorinated hydrocarbon based anion-exchange membrane and its method of preparation thereof. In the first step co-polymerization is carried out between N-isopropylacrylamide and 1-vinylimidazole. In the second step, obtained inter-polymer of isopropylacrylamide-co-vinylimidazole co-polymer is mixed with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) (IA-co-VI/PVDF-co-HFP), which is used for casting membrane film of desired thickness. The obtained casted membrane thin film is quaternized in methyl iodide solution.

A fuel cell system includes: a reformer which generates a reformed gas containing hydrogen by reacting hydrocarbon and moisture with each other; a fuel cell stack which generates electric energy through electrochemical reaction of the reformed gas and an oxidant; an ejector which, using steam as a drive fluid, sucks either a raw fuel containing the hydrocarbon or a recycled gas recovered from an anode exhaust gas, and supplies a resultant gas to the reformer; and a vaporizer which generates the steam by vaporizing water, wherein an operation temperature of the fuel cell stack is higher than a boiling point of water at an operation pressure, and the vaporizer generates the steam through heat exchange with the anode exhaust gas.

Disclosed is a stainless steel having excellent surface electrical conductivity for a fuel cell separator. According to an embodiment of the disclosed stainless steel having excellent surface electrical conductivity for a fuel cell separator, a value of the following surface oxide atomic ratio (1) may be 0.5 or less, as measured on the surface of a stainless steel containing 15 wt % or more of Cr by X-ray angle-resolved photoemission spectroscopy using an Al-Kα X-ray source under the condition where a take-off angle of photoelectrons is from 12° to 85°.

[00001]$\begin{array}{cc}\frac{\begin{array}{c}\mathrm{sum}\mathrm{of}\mathrm{atomic}\mathrm{concentrations}\left(\mathrm{at}\%\right)\\ \mathrm{of}\mathrm{metal}\mathrm{elements}\mathrm{in}\mathrm{metal}\mathrm{oxide}\left(\mathrm{MO}\right)\end{array}}{\begin{array}{c}\mathrm{sum}\mathrm{of}\mathrm{atomic}\mathrm{concentrations}\left(\mathrm{at}\%\right)\\ \mathrm{of}\mathrm{metal}\mathrm{elements}\mathrm{in}\mathrm{total}\mathrm{oxides}\mathrm{and}\mathrm{hydroxides}\end{array}}& \left(1\right)\end{array}$

The metal oxide (MO) includes a mixed oxide: M represents an alloying element other than Cr and Fe or a combination thereof in the matrix; and O represents oxygen. The total oxides and hydroxides include a Cr oxide, a Cr hydroxide, an Fe oxide, an Fe hydroxide, and the metal oxide (MO).

A novel polyfluorene-based ionomer, an anion exchange membrane, a method for preparing the polyfluorene-based ionomer, and a method for fabricating the anion exchange membrane are proposed. The polyfluorene-based ionomer contains no aryl ether bonds in the polymer backbone and includes piperidinium groups incorporated into the repeating units. The anion exchange membrane is fabricated from the polyfluorene-based ionomer. The anion exchange membrane has good thermal and chemical stability, excellent mechanical properties, and high ion conductivity. Due to these advantages, the anion exchange membrane can be applied as a membrane for an alkaline fuel cell and to a binder for an alkaline fuel cell or water electrolysis.

Me-N—C catalysts, wherein Me can include a transition metal, Mn, Fe, Co, or a combination of metals with Me-INU moieties located at the exterior surface of the Me-N—C catalysts are produced by a chemical vapor deposition synthesis. The synthesis methods can utilize non-solid-contact pyrolysis wherein a metal salt can be vaporized. Gaseous metal from the vaporized metal salt can displace a metal M from the N—C zeolitic imidazolate framework. The non-solid-contact pyrolysis does not mix solid iron precursors (e.g., Me=Mn, Fe, or Co) with the solid N—C zeolitic imidazolate framework precursors during or before the synthesis, which improves the process compared to conventional methods.

An insulation fault response method for a fuel cell vehicle, comprising: when a vehicle starts, detecting whether a fuel cell is in a startup state or not; when the fuel cell is not in the startup state, reading a first insulation resistance detected by a fuel cell control unit and a second insulation resistance detected by a cell management system; when the first insulation resistance indicates that the vehicle is in an insulation fault, executing a first control policy; and when the second insulation resistance indicates that the vehicle in an insulation fault, executing a second control policy, wherein the first control policy is different from the second control policy, and wherein when the first insulation resistance is less than a first threshold and/or the second insulation resistance is less than a second threshold, the vehicle is in an insulation fault.