Abstract: Disclosed are a fuel cell system, and a method of driving the system. The fuel cell system includes a fuel cell stack having a plurality of unit cells producing electricity, a switching unit connecting the plurality of unit cells to a discharge resistor, a switching controller synchronously operated when the voltage of the fuel cell stack reaches an open circuit voltage after power generation of the fuel cell stack is stopped. The switching controller generates select control signals to control the switching unit. The fuel cell system further includes a sensing unit measuring respective cell voltages of the plurality of unit cells and generating cell voltage sensing signals to control activation periods of the select control signals.

Abstract: A method of driving a fuel cell system according to embodiments of the present invention includes supplying a first amount of oxidizer (which is less than a normal amount of oxidizer) to a fuel cell stack while continuously supplying fuel to the fuel cell stack, supplying a second amount of oxidizer (which is more than the normal amount) to the fuel cell stack, and supplying a third amount of oxidizer (which is the normal amount of oxidizer supplied in a normal driving state) to the fuel cell stack.

Abstract: A fuel cell system optimizing the ratio of width of a channel to a width of a rib forming a passage for supplying fuel and air, the ratio of width thereof to a height of a channel, and the number of passages, thereby improving the fuel diffusing performance and reducing a pressure drop therein is provided. The fuel cell system includes at least one stack for generating electrical energy by an electrochemical reaction between hydrogen and oxygen, a fuel supply portion for supplying fuel to the stack, and an oxygen supply portion for supplying oxygen to the stack. The stack is formed into a stacked configuration having a plurality of membrane electrode assemblies separated by separators. The separators have ribs which closely contact the adjacent membrane electrode assemblies and form channels through which the oxygen and hydrogen flow. The ratio of the width of a channel to the height of the same is between about 0.6 and about 0.8.

Abstract: A stack for a fuel cell includes a first collecting plate having a first electric polarity, a second collecting plate having a second electric polarity different from the first electric polarity, and at least one electricity generator located between the collecting plates. The at least one electricity generator is for generating electric energy due to electrochemical reaction between hydrogen and oxygen to be collected by the collecting plates. Coupling members press the at least one electricity generator in an airtight connection between the collecting plates. A terminal member protrudes from the second collecting plate and is electrically connected to the first collecting plate and insulated from the second collecting plate, such that the terminal member is used as a first terminal having the first polarity. The second collecting plate or a second terminal member may also be used as a second terminal having the second polarity.

Abstract: The polymer electrolyte membrane of the present invention includes a porous supporter having pores, and a metal ion adsorptive material and a proton conductive polymer which are present in the pores of the porous supporter.

Abstract: A fuel supply device for a fuel cell and a fuel cell system using the same that prevent H2O, used in reforming from reaching and collecting in the fuel cell stack. The fuel supply device for a fuel cell includes a fuel reformer adapted to generate reformate via a reforming reaction, a gas-liquid separator coupled to an outlet of the fuel reformer, the gas-liquid separator being adapted to receive the reformate and control a moisture amount included within the reformate, a pipe coupled to an outlet of the gas-liquid separator, the pipe being adapted to pass the reformate and a condensed water removing device coupled with the pipe, the condensed water removing device being adapted to prevent condensed water within the reformate within the pipe from passing to an outside.

Abstract: A fuel cell system and a control method thereof are capable of preventing anode flooding due to a temperature difference between a stack and reformate upon starting a fuel cell system. The method of controlling a fuel cell system including steps of detecting a temperature of a fuel cell stack, detecting a temperature of reformate that is generated in a fuel reformer and then is supplied to the fuel cell stack through a heat exchanger, and setting the temperature of the reformate to be lower than the temperature of the fuel cell stack during a starting time of the fuel cell system.

Abstract: A fuel cell stack for generating electrical energy by an electrochemical reaction of a fuel and an oxidizing gas including a plurality of electricity generating units and a fastening member is disclosed. The plurality of electricity generating units are configured for an electrochemical reaction between the fuel and the oxidizing gas to generate electrical energy, and the fastening member combines the plurality of electricity generating units into a stack. Each electricity-generating unit includes a membrane electrode assembly (MEA) and separators that are provided on each side of the MEA. Each separator comprises a channel on a surface facing the MEA. The channel is divided into a multiple of 2 sub-channels that is greater than 2 on a surface of the separator, and the sub-channels have substantially the same fluid passage length.

Abstract: The present invention relates to a fuel cell capable of transferring a power generation state and coupling information of the fuel cell to an external apparatus and relates to an information device capable of receiving power and information from the fuel cell. The fuel cell includes a fuel cell stack for generating electricity by an electrochemical reaction of a fuel and an oxidant; a fuel supplier for supplying the fuel to the fuel cell stack; a set of output terminals for outputting electricity generated from the fuel cell stack and for outputting information on a power generation state of the fuel cell; and a power supply information processing unit for applying a voltage level according to the information to any one of the set of output terminals.

Abstract: A process of manufacturing a positive active material for a lithium secondary battery includes adding a metal source to a doping element-containing coating liquid to surface-treat the metal source, wherein the metal source is selected from the group consisting of cobalt, manganese, nickel, and combination thereof; drying the surface-treated metal source material to prepare a positive active material precursor; mixing the positive active material precursor with a lithium source; and subjecting the mixture to heat-treatment. Alternatively, the above drying step during preparation of the positive active material precursor is substituted by preheat-treatment or drying followed by preheat-treatment.

Abstract: Disclosed is a separator for a fuel cell stack. The separator includes a plate having a first opening and a second opening on a surface thereof. A field or a channel is formed on the surface of the plate. The field has a first end and a second end. A field inlet is formed on the surface of the plate and connects the first end of the field to the first opening, and a field outlet is formed on the surface of the plate and connects the second end of the field to the second opening. An area of a cross-section of the field inlet, which is cut perpendicular to the surface of the plate, is smaller than an area of a cross-section of the field outlet, which is cut perpendicular to the surface of the plate.

Abstract: A positive active material composition for a rechargeable lithium battery includes at least one lithiated compound, and at least one additive compound selected from the group consisting of a thermal-absorbent element-included hydroxide, a thermal-absorbent element-included oxyhydroxide, a thermal-absorbent element-included oxycarbonate, and a thermal-absorbent element-included hydroxycarbonate.

Abstract: The present invention relates to a positive active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery comprising the same. The positive active material includes a lithium/nickel-based compound wherein primary particles having an average particle diameter ranging from 1 ?m to 4 ?m are agglomerated to form secondary particles. The positive active material of the present invention has excellent electrochemical performance and outstanding inhibition to swelling at high temperatures.

Abstract: A fuel cell stack has an electrical generator including at least one unit cell between a pair of opposing end plates having a length and a width, wherein an aspect ratio of the length of the end plate to the width of the end plate is between about 1 to about 4. A center fastener penetrates the electrical generator through generally central regions of the end plates and a plurality of edge fasteners penetrates the electrical generator through generally peripheral regions of the end plates. The center fastener and the plurality of edge fasteners are adapted to press the end plates together.

Abstract: A fuel cell stack including an electricity generating unit for generating electrical energy by electrochemically reacting a fuel and an oxidizing agent, the electricity generating unit including: a first separator; a second separator; a membrane electrode assembly (MEA) between the first separator and the second separator, each of the first and second separators including a channel on a surface facing the MEA and a manifold in the surface facing the MEA, the manifold communicating with the channel; and a gasket, positioned at an outer circumference portion of an area where the MEA is positioned, for sealing a space between the first and second separators and for covering an open area of a channel extension area of at least one of the first and second separators where the manifold communicates with the channel.

Abstract: An air-breathing fuel cell stack including: a membrane electrode assembly that includes an anode, a cathode, and an electrolyte disposed therebetween; a fuel supplier coupled to the anode, to supply fuel to the anode; a cathode current collector coupled to the cathode; a cathode end plate to support the cathode current collector; and a filter positioned between the cathode current collector and the cathode end plate, to control the moisture content of the membrane electrode assembly.

Abstract: A process of manufacturing a positive active material for a lithium secondary battery includes adding a metal source to a doping element-containing coating liquid to surface-treat the metal source, wherein the metal source is selected from the group consisting of cobalt, manganese, nickel, and combination thereof; drying the surface-treated metal source material to prepare a positive active material precursor; mixing the positive active material precursor with a lithium source; and subjecting the mixture to heat-treatment. Alternatively, the above drying step during preparation of the positive active material precursor is substituted by preheat-treatment or drying followed by preheat-treatment.

Abstract: A fuel cell stack includes a plurality of membrane electrode assemblies (MEAs) and a stamped metal separator. The metal separator is positioned between the membrane electrode assemblies. The separator includes at least one channel on both surfaces of the separator formed by a stamping process. The separator comprises a plurality of holes, each of which form a manifold communicating with each the channels.

Abstract: A fuel cell stack comprising a multitude of membrane-electrode assemblies stacked with a separator interposed therebetween is characterized in that an MEA of first a property having an anode and a cathode, and the MEA of second property having an anode electrode and a cathode electrode are stacked. Preferably the MEA of the first property is a hydrocarbon-based MEA and the MEA of the second property is a fluorine-based MEA.

Abstract: A positive active material includes a core including a lithiated compound, and at least two surface-treatment layers formed on the core. The surface-treatment layer includes at least one compound selected from the group consisting of a coating-element-included hydroxide, a coating-element-included oxyhydroxide, a coating-element-included oxycarbonate, and a coating-element-included hydroxycarbonate. The coating element is selected from the group consisting of Mg, Al, Co, K, Na, Ca, Si, Ti, Sn, V, Ge, Ga, B, and As.