Abstract:
Embodiment methods for bypassing a fuel cell in a fuel cell stack include identifying a fuel cell to bypass and connecting a conductive bypass to the fuel cell stack such that the bypass electrically connects a first interconnect in the fuel cell stack and a second interconnect in the fuel cell stack and electrically bypasses the identified fuel cell. Further embodiment methods include applying a conductive sealing material to the fuel cell stack such that the conductive sealing material seals a cathode inlet or outlet of the identified fuel cell and such that the conductive sealing material electrically bypasses the identified fuel cell.
Abstract:
Die Erfindung betrifft ein Verfahren zur Erkennung und Lokalisierung von Defekten in einer Brennstoffzelle, bei dem die Spannung entlang der Kanten einer Bipolarplatte detektiert wird. Aus dem Verlauf der Spannungskurven selbst kann vorteilhaft auf das Vorhandensein eines stromlosen Bereichs geschlossen werden. Zudem kann aus der Lage der ermittelten Peakmaxima in den Spannungskurven auf die Position des stromlosen Bereichs geschlossen und dieser damit lokalisiert werden. Das Verfahren eignet sich insbesondere bei Brennstoffzellen, bzw. Brennstoffzellenstapeln aus Direkt-Methanol-Brennstoffzellen oder mit Wasserstoff betriebenen Brennstoffzellen. Sofern die Leitfähigkeit der Bipolarplatten nicht allzu hoch ist, ist das Verfahren auch bei Hochtemperatur-Brennstoffzellen einsetzbar.
Abstract:
The invention concerns an electric current production installation (10), for powering electrical members (12) of a vehicle, comprising at least two fuel cells (14) electrically connected in series via electric connection lines (20, 22). The invention is characterized in that each connecting line (20, 22) comprises a connecting switch (26), and in that it comprises bypass lines (28), each bypass line (28) comprising a bypass switch (30), so as to isolate at least one fuel cell (14) by selectively controlling the position of the connection and bypass switches (26, 30) of the lines (20, 22, 28) associated with that cell (14). The invention also concerns a method for monitoring such an installation.
Abstract:
A gas/liquid separation device is connected to a discharge valve which can discharge fuel gas to the outside of a fuel cell system along with water accumulated in the gas/liquid separation device. A change in pressure at a portion upstream of the discharge valve, which occurs due to an opening operation of the discharge valve, is detected or estimated, and an integral value is obtained by integrating the amount of change in the pressure with respect to time from when the discharge valve is opened or a parameter value corresponding to the integral value is obtained. The integral value represents an amount of fuel gas discharged due to the opening operation of the discharge valve. It is therefore possible to reliably discharge a desired amount of fuel gas by deciding a closing time at which the discharge valve is closed based on the integral value or the parameter value corresponding to the integral value.
Abstract:
The present invention relates to an improved fuel cell (10) and method for controlling same, having an anode and a cathode, which produces an electrical current having a given voltage and current output, and which includes a controller (122) electrically coupled to the fuel cell, and which shunts the electrical current between the anode and cathode of the fuel cell. The invention also includes a method for controlling the fuel cell having a given voltage and current output, and which includes determining the voltage and current output of the fuel cell, and shunting the electrical current between the anode and cathode of the fuel cell under first and second operational conditions.
Abstract:
The invention relates to a method of detecting a leak in a fuel cell system, having an anode branch comprising an anode compartment, in which a pressure prevailing in the anode compartment is established by actuating at least one control element for setting a mass flow rate for an anode gas which may be fed to the anode compartment, wherein the pressure is recorded as a function of time, and wherein in a cathode compartment of the fuel cell system at least one reference pressure (16, 28) is established by actuation of at least one control element, the profile over time of the pressure in the anode compartment dependent on the at least one reference pressure (16, 28) in the cathode compartment is recorded and any leak which may be present in the anode branch is detected as a function of the profile over time of the pressure. The invention additionally relates to a fuel cell system.
Abstract:
An electrochemical cell system is provided having: at least one electrochemical cell stack, each stack having at least one reactant fluid inlet; a pressure transmitter arranged in the at least one reactant fluid inlet of each stack; and a control unit for regulating the electrochemical cell system, the control unit receiving at least one signal value from the pressure transmitter indicative of the reactant fluid pressure. The control unit may compare the at least one signal value with a stored values and generate a leak indication based on the rate of pressure decay within the electrochemical cell system. A method of detecting and indicating a leak is also disclosed.
Abstract:
A gas/liquid separation device is connected to a discharge valve which can discharge fuel gas to the outside of a fuel cell system along with water accumulated in the gas/liquid separation device. A change in pressure at a portion upstream of the discharge valve, which occurs due to an opening operation of the discharge valve, is detected or estimated, and an integral value is obtained by integrating the amount of change in the pressure with respect to time from when the discharge valve is opened or a parameter value corresponding to the integral value is obtained. The integral value represents an amount of fuel gas discharged due to the opening operation of the discharge valve. It is therefore possible to reliably discharge a desired amount of fuel gas by deciding a closing time at which the discharge valve is closed based on the integral value or the parameter value corresponding to the integral value.