Abstract: The invention relates to an interconnector arrangement for a fuel cell stack, which can be brought into electrical contact with at least one membrane electrode assembly and which is arranged to separate a cathode flow field of the fuel cell stack from an anode flow field of the fuel cell stack. The invention is characterized in that the interconnector arrangement comprises a hollow space separated from the anode flow field and from the cathode flow field such that a flow of gas through the hollow space may not be more than five percent of flow-off gas through the cathode flow field or the anode flow field. The invention also relates to a fuel cell stack and to a method for manufacturing an interconnector arrangement.

Abstract: A repeating unit (10) for a fuel cell stack comprises a gas conducting region (8) for conducting a first gas (12) to and along an active surface (14). A barrier (16) is located in the gas conducting region. The gas conducting region comprises, at least over the active surface, a plurality of channels (20, 22, 24, 26, 28, 30, 32, 34) for conducting the first gas along the active surface. At least a first channel (26) among the plurality of channels defines a first flow direction at a first point (46) located closest to the barrier and a second flow direction at a second point (48), wherein a first straight line (50) which extends through the first point (46) and is parallel to the first flow direction misses the barrier (16) while a second straight line (52) which extends through the second point (48) and is parallel to the second flow direction intersects the barrier. The barrier (16) can he located upstream or downstream of the active surface (14).

Abstract: A fuel cell stack with a plurality of membrane electrode assemblies (MEAs) and a plurality of bipolar plates, wherein at least one surface of a first bipolar plate runs in undulating fashion, meandering fashion or zig-zag-shaped fashion and extreme points of the surface of the bipolar plate make contact with a first surface of a MEA at contact points. At least some of the contact points are associated with mating contact points on a second surface of the MEA, which surface is opposite the first surface of the MEA, with a surface of a second bipolar plate making contact with said mating contact points, and that the contact points and the associated mating contact points are positioned one above the other in the stacking direction. A method for producing a fuel cell stack is provided. A bipolar plate for a fuel cell stack is also provided.

Abstract: The invention relates to a contact arrangement for a fuel cell stack, especially for an SOFC fuel cell stack, comprising an interconnector arrangement which is arranged to establish an electrically conducting connection via at least one contact element on the anode side and at least one such element on the cathode side between an anode of a first membrane electrode assembly and a cathode of a second membrane electrode assembly. The invention is characterized in that at least one component to be sintered is provided on only one side of the interconnector arrangement, on the side of the interconnector arrangement facing the anode or the one facing the cathode, the component being coupled to the first or second membrane electrode assembly in such a manner that the electrically conducting connection can be established via the contact element on the anode side or via that on the cathode side by sintering the component to be sintered.

Abstract: The invention relates to a repeating unit for a fuel cell stack comprising a membrane electrode assembly and a flow field designed to supply an active surface of the membrane electrode assembly with gas and comprising at least a gas passage orifice. According to the invention it is contemplated that a gas-tight gas flow barrier is disposed between the active surface and the gas passage orifice so that gas passing through the first gas passage orifice flows around the gas flow barrier, wherein the projection of the gas flow barrier towards the periphery of the active surface is at least half as long as the projection of the gas passage orifice towards the periphery of the active surface.

Abstract: The present invention describes a control device for determining an actual fuel turnover for a fuel cell arrangement comprising a voltage reception device for receiving values of a voltage applying over the fuel cell arrangement, a fuel flow setting device for setting a flow of fuel supplied or suppliable to a fuel cell arrangement and/or a current setting device for setting an electrical current output by the fuel cell arrangement, as well as a memory for storing calibration data describing a nominal relation between the fuel turnover of the fuel cell arrangement and a voltage applying over the fuel cell arrangement. The control device is adapted to receive a first voltage value; to control a variation of the flow of fuel supplied to the fuel cell arrangement and/or the current output by the fuel cell arrangement after receiving the first voltage value; and to receive a second voltage value after the variation.

Abstract: The invention relates to an interconnector arrangement for a fuel cell stack, which can be brought into electrical contact with at least one membrane electrode assembly and which is arranged to separate a cathode flow field of the fuel cell stack from an anode flow field of the fuel cell stack. The invention is characterized in that the interconnector arrangement comprises a hollow space separated from the anode flow field and from the cathode flow field such that a flow of gas through the hollow space may not be more than five percent of flow-off gas through the cathode flow field or the anode flow field. The invention also relates to a fuel cell stack and to a method for manufacturing an interconnector arrangement.

Abstract: A repeating unit (10) for a fuel cell stack comprises a gas conducting region (8) for conducting a first gas (12) to and along an active surface (14). A barrier (16) is located in the gas conducting region. The gas conducting region comprises, at least over the active surface, a plurality of channels (20, 22, 24, 26, 28, 30, 32, 34) for conducting the first gas along the active surface. At least a first channel (26) among the plurality of channels defines a first flow direction at a first point (46) located closest to the barrier and a second flow direction at a second point (48), wherein a first straight line (50) which extends through the first point (46) and is parallel to the first flow direction misses the barrier (16) while a second straight line (52) which extends through the second point (48) and is parallel to the second flow direction intersects the barrier. The barrier (16) can be located upstream or downstream of the active surface (14).

Abstract: The invention relates to a fuel cell stack with a plurality of membrane electrode assemblies (MEAs) and a plurality of bipolar plates, wherein at least one surface of a first bipolar plate runs in undulating fashion, meandering fashion or zig-zag-shaped fashion and extreme points of the surface of the bipolar plate make contact with a first surface of a MEA at contact points. The invention provides that at least some of the contact points are associated with mating contact points on a second surface of the MEA, which surface is opposite the first surface of the MEA, with a surface of a second bipolar plate making contact with said mating contact points, and that the contact points and the associated mating contact points are positioned one above the other in the stacking direction. The invention also relates to a method for producing a fuel cell stack.

Abstract: A composite conductor for electric current comprises a core made of a first material and a jacket made of a second material, wherein the second material has a lower electrical conductivity than the first material. The second material is oxidation-resistant at temperatures up to at least 600° C., in particular at temperatures up to at least 800° C., in particular at temperatures up to at least 900° C. A fuel cell system comprises at least one fuel cell, to which a composite conductor according to the present invention is connected. A manufacturing method for a composite conductor comprises following steps: Provision of a core made of a first material and encasing the core by a second material having a lower electrical conductivity than the first material. The second material is oxidation-resistant at temperatures up to at least 600° C., in particular at temperatures up to at least 800° C., in particular at temperatures up to at least 900° C.

Abstract: The invention relates to a repeating unit for a fuel cell stack comprising a membrane electrode assembly and a flow field designed to supply an active surface of the membrane electrode assembly with gas and comprising at least a gas passage orifice. According to the invention it is contemplated that a gas-tight gas flow barrier is disposed between the active surface and the gas passage orifice so that gas passing through the first gas passage orifice flows around the gas flow barrier, wherein the projection of the gas flow barrier towards the periphery of the active surface is at least half as long as the projection of the gas passage orifice towards the periphery of the active surface.

Abstract: The invention relates to a bracing plate for bracing a fuel cell stack. According to the invention it is contemplated that the bracing plate is formed of a plurality of layers, a first layer facing the fuel cell stack and a second layer disposed adjacent to the first layer and arranged on the side opposing the fuel cell stack being provided, the second layer having a higher bending rigidity than the first layer.

Abstract: The invention relates to an interconnector arrangement for a fuel cell stack, which arrangement can be brought into electrical contact with at least one membrane electrode assembly of the fuel cell stack. The invention is characterized in that the interconnector arrangement comprises a nickel foam which is interposed between at least one housing part of the interconnector arrangement and the membrane electrode assembly to establish an electrically conducting connection. The invention also relates to a method for manufacturing a contact arrangement for a fuel cell stack.

Abstract: The invention relates to a contact arrangement for a fuel cell stack, especially for an SOFC fuel cell stack, comprising an interconnector arrangement which is arranged to establish an electrically conducting connection via at least one contact element on the anode side and at least one such element on the cathode side between an anode of a first membrane electrode assembly and a cathode of a second membrane electrode assembly. The invention is characterized in that at least one component to be sintered is provided on only one side of the interconnector arrangement, on the side of the interconnector arrangement facing the anode or the one facing the cathode, the component being coupled to the first or second membrane electrode assembly in such a manner that the electrically conducting connection can be established via the contact element on the anode side or via that on the cathode side by sintering the component to be sintered.

Abstract: The invention relates to a fuel cell system comprising a reformer for generating a reformate from a fuel and an oxidising agent, a fuel cell for converting the reformate into a depleted reformate and electric energy, and a recirculation conduit for partly returning the depleted reformate to the reformer. In this connection the invention is advantageously characterised in that a delivery device is provided by means of which the fuel as well as the depleted reformate from the recirculation conduit are supplyable to the reformer. The invention further relates to a method for operating such a fuel cell system.

Abstract: The invention relates to a sealing for the gas-tight connection of two elements of a fuel cell stack comprising an electrically non-conducting spacer component and at least one solder component solid or viscous over its entire extension at the operating temperature of the fuel cell stack and coupling the spacer component to at least one of the elements to be connected of the fuel cell stack in a gas-tight manner. According to the invention it is envisaged that the spacer component is formed of a ceramic material. The invention further relates to a fuel cell stack in which, according to the invention, it is envisaged that a distribution of forces compressing the fuel cell stack in the axial direction is directly transmitted to at least one of the elements to be connected by the spacer component. The invention further relates to production methods for seals and fuel cell stacks.

Abstract: The invention relates to a method for testing the leak-tightness of a fuel cell stack comprising the steps of operating the fuel cell stack using defined gas supply rates, a defined modification of at least one gas supply rate, detecting at least one cell or cell group voltage and analysing the variation in time of the at least one cell or cell group voltage.

Abstract: The invention relates to a test stand for a fuel cell stack comprising an insulating device for thermally insulating the fuel cell stack, a media supply device for supplying a gaseous fuel and an oxidising agent to the fuel cell stack and an electronic control device for controlling and/or regulating as well as for monitoring a test method. The invention further relates to a test method for a fuel cell stack.

Abstract: A process and device for determination of the lambda value (?actual) of reformate (10) which is to be supplied to a fuel cell stack (12), by determining the lambda value (?actual) of the no-load voltage (U0) of the voltage on at least one fuel cell element (14). Furthermore, a process and device for lambda control of a reformer, utilizes the process and device for determining the lambda value to controller an actuator of a lambda-controlled reformer (16) for reaction of at least fuel (20) and air (22) into reformate (10), the reformer being connected to a fuel cell stack (12) to supply reformate (10) form the reformer (16) to the fuel stack (12).

Abstract: The invention relates to a SOFC stack with bipolar plates (5) for connecting the electrodes (3, 4) of two neighboring fuel cells having a ceramic electrolyte, where the bipolar plates (5) have one base plate (6) each, and connected to it, one or more contact elements (7) on one on both sides of the base plate (6). The bipolar plates are characterized in that the base plate (6) is rigid and gas-tight and the contact elements (7) are elastically or plastically deformable, and are arranged or implemented in such a way that they are permeable to gas perpendicularly to the plane of the base plate (6). The bipolar plates (5) mechanically stabilize the SOFC stack and ensure the reliable contacting of the electrodes (3, 4), wherein manufacturing tolerances of the electrodes (3, 4) and relative movements between the components of the stack are compensated by thermal expansion or creep processes.