Abstract: To provide a space-saving bipolar plate for a fuel cell comprising an anode plate and a cathode plate, anode gas channels and cathode gas channels lead from main gas ports on opposite sides into an active area and are distributed across the width of said area such that they are subsequently diverted towards an opposite distribution area, and the coolant channels branch in the distribution area and, after branching, are diverted towards the anode gas channels and towards the cathode gas channels and, in each region of overlap with the anode gas channels and the cathode gas channels, are diverted collectively such that the coolant channels lead, together with the anode gas channels and the cathode gas channels, into the active area with no overlap and alternatingly with said anode gas channels and cathode gas channels.

Abstract: A bipolar plate seal assembly for a fuel cell is provided. The bipolar plate seal assembly includes: a bipolar plate having a flow field for a reactant medium on at least one of its main sides, and a supply area arranged adjacent to the flow field, in which supply ports for feeding and discharging the reactant medium and optionally for feeding and discharging a coolant are arranged; and at least one seal assembly having an electrically insulating layer covering at least one or more sections of the supply area of the bipolar plate and having recesses that correspond to the supply ports of the bipolar plate, and for each recess, a seal circumferential thereto.

Abstract: The disclosure relates to a method for operating a fuel cell that comprises at least one individual cell with a membrane and catalysts, wherein humidity within the fuel cell is actively influenced as a function of a voltage of the fuel cell, and the method further includes specifying an initial humidity at an initial operating-point-related voltage, and specifying a second humidity that is lower than the first humidity at a second operating-point-related voltage that is higher than the first operating-point-related voltage. Furthermore, the disclosure relates to a fuel cell system that is configured to perform the method according to the disclosure.

Abstract: To provide a space-saving bipolar plate for a fuel cell comprising an anode plate and a cathode plate, anode gas channels and cathode gas channels lead from main gas ports on opposite sides into an active area and are distributed across the width of said area such that they are subsequently diverted towards an opposite distribution area, and the coolant channels branch in the distribution area and, after branching, are diverted towards the anode gas channels and towards the cathode gas channels and, in each region of overlap with the anode gas channels and the cathode gas channels, are diverted collectively such that the coolant channels lead, together with the anode gas channels and the cathode gas channels, into the active area with no overlap and alternatingly with said anode gas channels and cathode gas channels.

Abstract: A bipolar plate seal assembly for a fuel cell is provided. The bipolar plate seal assembly includes: a bipolar plate having a flow field for a reactant medium on at least one of its main sides, and a supply area arranged adjacent to the flow field, in which supply ports for feeding and discharging the reactant medium and optionally for feeding and discharging a coolant are arranged; and at least one seal assembly having an electrically insulating layer covering at least one or more sections of the supply area of the bipolar plate and having recesses that correspond to the supply ports of the bipolar plate, and for each recess, a seal circumferential thereto.

Abstract: The disclosure relates to a method for operating a fuel cell that comprises at least one individual cell with a membrane and catalysts, wherein humidity within the fuel cell is actively influenced as a function of a voltage of the fuel cell, and the method further includes specifying an initial humidity at an initial operating-point-related voltage, and specifying a second humidity that is lower than the first humidity at a second operating-point-related voltage that is higher than the first operating-point-related voltage. Furthermore, the disclosure relates to a fuel cell system that is configured to perform the method according to the disclosure.

Abstract: A bipolar plate for a fuel cell includes an anode side and a cathode side, wherein in a top view onto the anode side or cathode side: operating medium flow fields include an anode gas flow field situated on the anode side, a cathode gas flow field situated on the cathode side, and an internal coolant flow field, a first supply area and a second supply area situated on diametrically opposite sections of the bipolar plate lateral to the operating medium flow fields, supply ports situated in the first and second supply areas as through openings, an anode gas port for supplying or removing the anode gas, a cathode gas port for supplying or removing the cathode gas, and a coolant port for supplying or removing the coolant, the anode gas port being situated within a supply area between the cathode gas port and the coolant port, and the bipolar plate including or being made of a carbon-based electrically conductive material.

Abstract: Improved water distribution can be obtained within the cells of a fuel cell series stack by maintaining a suitable temperature difference between the cathode and anode sides of each cell in the stack during shutdown.

Abstract: A fuel cell system comprising a fuel cell stack and at least one hydration sensor apparatus for measuring membrane hydration in the fuel cell stack is disclosed. The hydration sensor apparatus comprises (1) an electrically insulated sensor comprising a polymer electrolyte membrane, (2) a power supply, and (3) a load resistor. The sensor, the power supply and the load resistor of the hydration sensor apparatus are electrically connected and the sensor of the hydration sensor apparatus is fluidly connected to the fuel cell stack such that, during operation of the fuel cell system, the polymer electrolyte membrane of the hydration sensor apparatus is exposed to a fuel fluid stream of the fuel cell stack.