Abstract: The present invention provides a purge system for a fuel cell, which can reduce the time required to thaw a frozen valve during cold start-up and reduce the whole start-up time, thus improving the cold start performance. In preferred embodiments, the present invention provides a purge system for a fuel cell with improved cold start performance, the system preferably including a main pipe connected to a purge gas outlet of a fuel cell stack to discharge a purge gas purging the fuel cell stack and impurities; an auxiliary pipe branched from the main pipe; a purge valve installed in each of the main pipe and the auxiliary pipe to perform an purge operation; a cut-off valve installed at an upstream side of the purge valve in the auxiliary pipe; and a controller for controlling the operation of the purge valves and the cut-off valve.

Abstract: The present invention provides a novel integrated valve system for a fuel cell stack, in which an air shut-off valve for preventing the inflow of air when a fuel cell shuts down and a dry gas purge valve for improving cold startability are coaxially coupled to each other so that the air shut-off valve and the dry gas purge valve simultaneously open or close.

Abstract: The present invention provides a fuel cell bipolar plate and a method for manufacturing the same, in which a carbon or metal fuel cell bipolar plate is surface-treated with a complex transition metal oxide, which is a main component of a variable resistance heating element having a negative temperature characteristic, so that the bipolar plate can ensure a sufficient amount of heat, required to prevent product water from freezing, by itself in a short time without any external energy, thus improving cold start performance of a fuel cell vehicle at a temperature below zero.

Abstract: The present invention provides a startup control device and method for a fuel cell system. The startup control device includes a concentration meter, a hydrogen feed rate controller, and a controller. The concentration meter measures the concentration of oxygen located in the anode of a fuel cell stack. The hydrogen feed rate controller is disposed at an inlet of the anode. The controller receives an oxygen concentration signal value from the concentration meter while controlling the hydrogen feed rate controller to adjust a hydrogen feed rate to the anode.

Abstract: The present invention provides a fuel cell stack with enhanced freeze-thaw durability. In particular, the fuel cell stack includes a gas diffusion layer between a membrane-electrode assembly and a bipolar plate. The gas diffusion layer has a structure that reduces contact resistance in a fuel cell and is cut at a certain angle such that the machine direction (high stiffness direction) of GDL roll is not in parallel with the major flow field direction of the bipolar plate, resulting in an increased GDL stiffness in a width direction perpendicular to a major flow field direction of a bipolar plate.

Abstract: The present invention provides a purging device and method for improving cold start performance of a fuel cell by direct heating, in which a gas mixture of hydrogen and air is supplied to a cathode of a fuel cell stack after shutdown of a fuel cell system to generate heat by a reaction of hydrogen and air, and the generated heat is used to increase the temperature of the fuel cell stack and, at the same time, remove water from the fuel cell stack.

Abstract: The present invention provides an apparatus and method for determining deterioration of a fuel cell, the method including measuring in real time fluoride ion concentration or pH value of outflow water from a fuel cell stack during operation in a fuel cell vehicle, calculating a fluoride emission rate from the measured value and, if the calculated fluoride emission rate is out of a predetermined normal range, determining deterioration of an electrolyte membrane of the fuel cell stack.

Abstract: Apparatuses and methods for accelerated activation of fuel cells are disclosed. The apparatuses include a fuel cell stack; an air supplying means coupled to a cathode catalyst side of the fuel cell stack through a mass flow controller and a humidifier; a hydrogen supplying means coupled to an anode catalyst side of the fuel cell stack through a mass flow controller and a humidifier; and a cable coupled to both ends of the fuel cell stack for short-circuiting the cathode and the anode.

Abstract: Features is a fuel cell system including: a stack consisting of a plurality of unit cells generating electrical energy by means of electrochemical reaction of a fuel and an oxidizing agent; a fuel supply connected to the stack through a first connecting line to supply the fuel to the stack; an oxidizing agent supply connected to the stack through a second connecting line to supply the oxidizing agent to the stack; a burner mounted on the second connecting line and generating heat by means of oxidizing catalytic reaction of the fuel and oxidizing agent; a mixing valve mounted on a third connecting line which connects the first connecting line with the second connecting line and supplying the fuel and the oxidizing agent to the burner; and a heater mounted at the burner, generating heat by electricity, and supplying the heat to the burner.

Abstract: The present invention provides a method for determining the occurrence of ice blocking in an electrode surface in real time by analyzing minimum cell voltages of a fuel cell stack and, at the same time, distinguishing the occurrence of ice blocking in an anode from the occurrence of ice blocking in a cathode.

Abstract: The present invention provides a purge system for a fuel cell, which can reduce the time required to thaw a frozen valve during cold start-up and reduce the whole start-up time, thus improving the cold start performance. In preferred embodiments, the present invention provides a purge system for a fuel cell with improved cold start performance, the system preferably including a main pipe connected to a purge gas outlet of a fuel cell stack to discharge a purge gas purging the fuel cell stack and impurities; an auxiliary pipe branched from the main pipe; a purge valve installed in each of the main pipe and the auxiliary pipe to perform an purge operation; a cut-off valve installed at an upstream side of the purge valve in the auxiliary pipe; and a controller for controlling the operation of the purge valves and the cut-off valve.

Abstract: A method for shutting down a fuel cell system includes: determining whether an outside air temperature is below a first predetermined reference temperature when a shutdown of a fuel cell system is detected; warming up the fuel cell stack by operating balance of plant components of the fuel cell system and a stack load using the power of the fuel cell stack, while the supply of hydrogen to the fuel cell stack is normally maintained, when the outside air temperature is below the first reference temperature; removing water in the fuel cell stack by passing air supplied by an air supply system through the stack load to supply heated air to a cathode of the fuel cell stack; and shutting down the fuel cell system by cutting off the supply of air after the removal of water. The method can eliminate or reduce cold start failure.

Abstract: The present invention provides a novel integrated valve system for a fuel cell stack, in which an air shut-off valve for preventing the inflow of air when a fuel cell shuts down and a dry gas purge valve for improving cold startability are coaxially coupled to each other so that the air shut-off valve and the dry gas purge valve simultaneously open or close.

Abstract: The present invention provides a sealing structure of a sealing portion for maintaining the airtightness of a coolant passage in two stacked separators of a fuel cell, wherein a groove in which an adhesive is to be filled is formed on a surface of one of two separators, and dam portions are formed on both sides of the groove to prevent the adhesive applied in the groove from overflowing into a connection passage and a coolant passage. Accordingly, the adhesive overflowing from the groove when the two separators are bonded to each other by applying a pressure is collected in the dam portions to form three sealing lines, thus improving the airtightness of the sealing portion. Moreover, it is possible to solve the problem that the performance of the fuel cell stack is deteriorated when an antifreeze/coolant leaks from the coolant passage to an MEA, in which the fuel cell reaction takes place, or the leaking coolant contaminates a catalyst of the MEA.

Abstract: The method of activating a vehicle fuel cell for ensuring maximum performance, improves performance of a polymer electrolyte membrane fuel cell, reduces a hydrogen usage, and has stable performance after manufactured. The method includes: placing a fuel cell in an activation device so as to be activated; changing a humidification state of a humidifier which supplies vapor to the fuel cell and a state of a cooling water; supplying a reactant gas to the fuel cell and maintaining a no-load state; maintaining a load state while changing a flow rate of the vapor and gas supplied to the fuel cell; changing the sate of the fuel cell to the no-load state, and re-supplying the reactant gas to the fuel cell; and comparing data measured when the fuel cell operates in the no-load state and data measured when the fuel cell operates in the load state respectively with a reference value.

Abstract: Apparatuses and methods for accelerated activation of fuel cells are disclosed. The apparatuses include a fuel cell stack; an air supplying means coupled to a cathode catalyst side of the fuel cell stack through a mass flow controller and a humidifier; a hydrogen supplying means coupled to an anode catalyst side of the fuel cell stack through a mass flow controller and a humidifier; and a cable coupled to both ends of the fuel cell stack for short-circuiting the cathode and the anode.

Abstract: A separating plate for a fuel cell includes first and second plates, each provided with a hydrogen channel, an oxygen channel, and a coolant channel. The first and second plates are attached to one another to form a main plate such that the first and second hydrogen, oxygen, and coolant channels compose main hydrogen, oxygen, and coolant channels, respectively. The main hydrogen and oxygen channels are fluidly isolated from each other. Distal ends of the main channels each communicate with a manifold through a communication passageway configured to supply hydrogen, oxygen, or coolant to a corresponding one of the main channels.

Abstract: The present invention provides an apparatus and method for determining deterioration of a fuel cell, the method including measuring in real time fluoride ion concentration or pH value of outflow water from a fuel cell stack during operation in a fuel cell vehicle, calculating a fluoride emission rate from the measured value and, if the calculated fluoride emission rate is out of a predetermined normal range, determining deterioration of an electrolyte membrane of the fuel cell stack.

Abstract: The present invention provides a fuel cell bipolar plate and a method for manufacturing the same, in which a carbon or metal fuel cell bipolar plate is surface-treated with a complex transition metal oxide, which is a main component of a variable resistance heating element having a negative temperature characteristic, so that the bipolar plate can ensure a sufficient amount of heat, required to prevent product water from freezing, by itself in a short time without any external energy, thus improving cold start performance of a fuel cell vehicle at a temperature below zero.

Abstract: The present invention provides a method for accelerating activation of a fuel cell, which can significantly reduce the time required for the activation of the fuel cell and the amount of hydrogen used and facilitate the activation of the fuel cell.