Abstract: A method and a system for starting a fuel cell at temperatures below 0° Celsius with a two-phase cooling system are indicated, whereby the two-phase cooling system has a pump to convey a coolant present in the two-phase cooling system, whereby the coolant is present at least partially in a gas phase in the two-phase cooling system, including steps of starting the fuel cell, and activating the pump after a defined period of time, whereby the coolant is present substantially in the gas phase within the fuel cell during the defined period of time.

Abstract: A fuel cell system having a two-phase cooling system includes at least one fuel cell having a coolant inlet and a coolant outlet, an accumulator in fluid connection with the fuel cell to contain coolant which flows out of the fuel cell in a liquid phase in a first portion and in a gas phase in a second portion, a condenser in fluid connection with the accumulator to condense and supercool the coolant, a thermally conductive element between the coolant inlet and the coolant outlet to transfer heat from the coolant outlet to the coolant inlet.

Abstract: A bipolar plate for a fuel cell having a two-phase cooling system and a fuel cell system includes a coolant inlet, a coolant outlet, and coolant channels with the coolant inlet being in fluid connection with the coolant outlet via the coolant channels. At least one inner surface of coolant inlet, coolant outlet and at least one of the coolant channels has a surface treatment to influence a flow regime of a cooling fluid along at least one inner surface and/or a phase transition of the cooling fluid.

Abstract: A fuel cell system having a two-phase cooling system includes at least one fuel cell with a coolant inlet and a coolant outlet, a condenser to condense and to supercool the coolant, a pump to pump the supercooled coolant, and at least one ejector fluidically connected to the coolant outlet, the pump, the condenser and the fuel cell to supply the coolant to the fuel cell.

Abstract: A fuel cell system having a two-phase cooling system includes at least one fuel cell having a coolant inlet and a coolant outlet, a condenser in fluid connection with the accumulator to condense and supercool the coolant, a bypass line including a pump, the bypass line being in fluid connection with the coolant outlet and the coolant inlet and being adapted to return the coolant to the fuel cell by a pump.

Abstract: A method and system for reducing temperature peaks during start-up of a fuel cell with a two-phase cooling system, the method including setting a saturation pressure of a coolant, via a pressure controller, to a first saturation pressure such that a maximum temperature of a coolant induced by boiling delay is below a maximum operating temperature of the fuel cell, starting the fuel cell, in response to the maximum temperature of the coolant induced by boiling delay being exceeded, setting the saturation pressure of the coolant, via the pressure controller, to a second saturation pressure, wherein the second saturation pressure is higher than the first saturation pressure.

Abstract: A separator plate (1) for media guiding in a fuel cell, with at least one through-opening (2, 3, 4, 5, 6, 7) for supplying and at least one through-opening (2, 3, 4, 5, 6, 7) for discharging a medium, with a channel structure (12) for uniformly guiding the medium, as well as with distribution regions (9) which connect the through-openings (2, 3, 4, 5, 6, 7) with the channel structure (12). At least one of the distribution regions (9) surrounds at least one of the through-openings (2, 3, 4, 5, 6, 7) associated with it around the entire perimeter.

Abstract: A separator plate (1) for media guiding in a fuel cell, with at least one through-opening (2, 3, 4, 5, 6, 7) for supplying and at least one through-opening (2, 3, 4, 5, 6, 7) for discharging a medium, with a channel structure (12) for uniformly guiding the medium, as well as with distribution regions (9) which connect the through-openings (2, 3, 4, 5, 6, 7) with the channel structure (12). At least one of the distribution regions (9) surrounds at least one of the through-openings (2, 3, 4, 5, 6, 7) associated with it around the entire perimeter.

Abstract: The invention relates to bipolar plates for fuel cell systems. According to the invention, the component sheets of a bipolar plate (1) are formed for a welded joint (4, 5), such that between the profile regions (6) of the channel ducts (2), only small local surfaces remain as welding zones (10). The above is achieved by means of a corresponding shape of the profile molding (8, 9) of the component sheets. As a result of said reduction of the welding zones to small regions of the total surface, a larger proportion of the area is available for the channels (2), in other words, the channel cross-section and hence the coolant flow can be increased. At the same time the structure for the use of gas diffusion layers made from non-wovens, textiles or paper can be optimized.

Abstract: The invention relates to a bipolar plate for a fuel cell stack, which comprises at least a an anode-side sub-plate. An interior of the bipolar plate is enclosed by the sub-plates, with a fluid port area arranged having at least one fluid port, over which a fluid can be conveyed to the fluid channels. The fluid channels are arranged on at least one of the flat sides, as well as a manifold zone, over which the fluid can be distributed to its assigned fluid channels and an accumulation zone, over which the fluid can be carried away from the fluid channels to another fluid port area. At least one of the sub-plates has a uniform arrangement of raised support points in the manifold zone and/or accumulation zone. Apart from the peripherally situated support points, a negative support point of the same type is designed adjacent to each raised support point inside the manifold zone and/or the accumulation zone.

Abstract: The invention relates to a bipolar plate (3) for a fuel cell arrangement (1), in particular for placement between two adjacent membrane electrode arrangements, comprising at least one or two plates disposed plane-parallel relative to one another, wherein a flow field (F) is formed from the channel structures made in the respective plate at least on one or both outer sides, respectively, said channel structures comprising a plurality of channels (K) running between a fluid inlet (E) and a fluid outlet (A) and webs (S) running between two channels (K). According to the invention, the channels (K) and/or the webs (S) comprise at least one varying channel width (b1), one varying web width (b2) and/or one varying channel distance (a) on at least one of the outer sides along a flow direction (R) of a fluid between the fluid inlet (E) and the fluid outlet (A).

Abstract: The invention relates to bipolar plates for fuel cell systems. According to the invention, the component sheets of a bipolar plate (1) are formed for a welded joint (4, 5), such that between the profile regions (6) of the channel ducts (2), only small local surfaces remain as welding zones (10). The above is achieved by means of a corresponding shape of the profile molding (8, 9) of the component sheets. As a result of said reduction of the welding zones to small regions of the total surface, a larger proportion of the area is available for the channels (2), in other words, the channel cross-section and hence the coolant flow can be increased. At the same time the structure for the use of gas diffusion layers made from non-wovens, textiles or paper can be optimized.

Abstract: The invention relates to a bipolar plate for a fuel cell stack, which comprises at least a an anode-side sub-plate. An interior of the bipolar plate is enclosed by the sub-plates, with a fluid port area arranged having at least one fluid port, over which a fluid can be conveyed to the fluid channels. The fluid channels are arranged on at least one of the flat sides, as well as a manifold zone, over which the fluid can be distributed to its assigned fluid channels and an accumulation zone, over which the fluid can be carried away from the fluid channels to another fluid port area. At least one of the sub-plates has a uniform arrangement of raised support points in the manifold zone and/or accumulation zone. Apart from the peripherally situated support points, a negative support point of the same type is designed adjacent to each raised support point inside the manifold zone and/or the accumulation zone.

Abstract: An electrochemical fuel cell stack includes a membrane electrode assembly and a distributor plate. The distributor plate includes a channel region having gas channels for distributing reaction gas to the membrane electrode assembly, a first port area for supplying reaction gas to the channel region, and a second port area for removing reaction gas from the channel region. The gas channels are disentangled and each distributed in a respective separate channel area, at least one of the gas channels having at least one deflection point between the first and second port areas.

Abstract: The invention relates to a fuel cell stack, comprising alternately arranged membrane-electrode units (3) and separator plates (2, 2a) for the introduction and removal of the reactant and oxidative fluid, whereby the separator plate (2, 2a) has a surface structure and the opposing face has the negative surface structure, by means of a shaping process. According to the invention, on stacking the separator plates (2, 2a), the surface structure of a separator plate (2) is opposite the corresponding negative surface structure of the neighboring separator plate (2a).

Abstract: The invention relates to an electrochemical fuel cell stack comprising a membrane-electrode-unit and a distributor plate comprising a channel area with gas channels for distributing anode or cathode gas to the membrane-electrode-unit, a portal area for supplying anode and/or cathode gas into the channel area and a portal area for removing anode and/or cathode gas from the channel area. According to the invention, the gas channels in the channel area of the distributor plate are not combined in a bundle but are disentangled and distributed over on a plurality of separated channel regions. A gas channel extends exactly in a channel region, with at least one deviation between the portal areas for supplying and removing anode and/or cathode gas.