Abstract: A method of compressing a gas includes pumping, using a pump, at least a portion of a liquid contained in a first chamber to a second chamber containing a gas at a first pressure such that the portion of the liquid pumped into the second chamber compresses the gas in the second chamber to a second pressure greater than the first pressure, wherein the portion of the liquid pumped into the second chamber is admitted into the second chamber so that the admitted liquid flows along an internal surface of the second chamber.

Abstract: A method of compressing a gas includes pumping, using a pump, at least a portion of a liquid contained in a first chamber to a second chamber containing a gas at a first pressure such that the portion of the liquid pumped into the second chamber compresses the gas in the second chamber to a second pressure greater than the first pressure, wherein the portion of the liquid pumped into the second chamber is admitted into the second chamber so that the admitted liquid flows along an internal surface of the second chamber.

Abstract: A method of compressing a gas includes maintaining a first volume of liquid in a first high pressure chamber and maintaining a first volume of gas in a second high pressure chamber, wherein the first volume of gas is at a first pressure and the first high pressure chamber and the second high pressure chamber are fluidly connected through a high pressure pump. A pressurized gas is forced into the first high pressure chamber having the first volume of liquid and simultaneously pumping, using the high pressure pump, at least a portion of the first volume of liquid in the first high pressure chamber to the second high pressure chamber, wherein the first volume of liquid pumped into the second high pressure chamber compresses the first volume of gas in the second high pressure chamber to a second pressure greater than the first pressure.

Abstract: Method and apparatus for cooling a fuel cell stack. The cooling system uses vaporization cooling of the fuel stack and supersonic vapor compression of the vaporized coolant to significantly increase the temperature and pressure of the liquid coolant flowing through a heat exchanger. By increasing the heat rejection temperature of the coolant delivered to the heat exchanger, the heat transfer area of the heat exchanger can be reduced and the mass flow rate of coolant can also be reduced. The increased fluid pressure is used to circulate the coolant through the cooling system, thereby eliminating the circulation pump associated with conventional systems.

Abstract: According to the present invention, a stacked electrochemical conversion assembly is provided with an electrically and thermally insulating plate within one or both of the end unit assemblies of the stack. For example, in accordance with one embodiment of the present invention, the electrochemical conversion assembly includes at least one end unit assembly comprising an electrically conductive terminal plate and an electrically insulating plate interposed between the terminal plate and an end unit plate of the end unit assembly. The electrically insulating plate comprises an array of thermally insulating regions defined therein.

Abstract: In at least one embodiment, the present invention provides an electrically conductive fluid distribution plate and a method of making, and system for using, the electrically conductive fluid distribution plate. In at least one embodiment, the plate comprises a plate body defining a set of fluid flow channels configured to distribute flow of a fluid across at least one side of the plate, and a polymeric porous conductive layer proximate the plate body, with the porous conductive layer having a porosity sufficient to result in a water contact angle of the surface of less than 40°.

Abstract: In at least one embodiment, the present invention provides an electrically conductive fluid distribution plate and a method of making, and system for using, the electrically conductive fluid distribution plate. The plate comprises a plate body having a surface defining a set of fluid flow channels configured to distribute flow of a fluid across at least one side of the plate, at least a portion of the surface having a roughness average of 0.5 to 5 ?m and a contact resistance of less than 40 mohm cm2 when sandwiched between carbon papers at 200 psi.

Abstract: In at least one embodiment, the present invention provides a hydrophilic electrically conductive fluid distribution plate and a method of making, and system for using, the hydrophilic electrically conductive fluid distribution plate. In at least one embodiment, the plate comprises a plate body defining a set of fluid flow channels configured to distribute flow of a fluid across at least one side of the plate, and a composite conductive coating having a water contact angle of less than 40° adhered to the plate body. In at least one embodiment, the composite coating comprises a polymeric conductive layer adhered to the plate body having an exterior surface, and a particulate carbon layer adhered to the exterior surface of the polymeric conductive layer.

Abstract: An electroconductive porous substrate such as carbon fiber paper with an electroconductive polymer deposited on the carbon fibers of the paper is used as a wicking material or diffusion medium in a fuel cell. The polymer may be deposited from a solution of monomers by electrochemical polymerization.

Abstract: The present invention isolates the fluid streams flowing into and out of a fuel cell stack from the terminal plates so that the fluid streams and terminal plates do not come into contact with one another. The prevention of the fluid streams from contacting the terminal plate eliminates corrosion concerns associated with the terminal plate. The present invention accomplishes this isolation through the use of headers having fluid passageways therein that route the fluid streams in and/or out of the fuel cell stack while preventing contact between the fluid streams and the terminal plate.

Abstract: An improved bipolar plate stainless steel alloy comprises, in weight percent, about 20% to about 30% chromium, about 10% to about 25% nickel, about 1% to about 9 % molybdenum, and up to about 4% copper, where the weight percentage of chromium plus nickel plus molybdenum is greater than about 51 percent. The weight percentage of chromium plus molybdenum may be greater than about 1.66 times the weight percentage of nickel. In addition, the ratio of chromium equivalents to nickel equivalents may be greater than about 1.66.

Abstract: A fuel cell including an anode-side catalyst coated membrane and a cathode-side catalyst coated membrane. At least a portion of a reduced-permeability layer is disposed between the ionically conductive membrane and the anode-side and cathode-side gas diffusion media, wherein the reduced-permeability layer is formed of a material that has a permeability that is less than a permeability of the ionically conductive member. The reduced-permeability layer may also be formed of a material that is softer than-the ionically conductive membrane.

Abstract: A thermal management system of an electrochemical engine comprises a radiator provided with a wicking mechanism, a coolant pump fluidly connected to the radiator, a water tank, and a water pump. The water tank is located in the void spaces around fuel storage tanks, and may be filled directly or with reclaimed water from a vapor by-product of the electrochemical engine. The water pump is operable to supply water from the water tank to the wicking mechanism during peak power and/or hot day conditions. Moisture in the vapor by-product may be condensed with the excess cooling capacity of the radiator under less severe cooling conditions. Under freezing conditions, exhaust or coolant from the electrochemical engine may be used to unfreeze water in the tank and wicking mechanism supply lines.

Abstract: The present invention is directed to an electroconductive element within an electrochemical cell that improves water management. The electroconductive element comprises an impermeable electrically conductive element and a porous liquid distribution media disposed along a major surface of the conductive element. Preferably, the liquid distribution media is in direct contact and fluid communication with a fluid distribution layer disposed between the membrane electrode assembly (MEA) and the liquid distribution media, so that liquids are drawn from the MEA through the fluid distribution layer to and through the liquid distribution media. The liquid distribution media transports liquids away from the MEA in the fuel cell. Methods of fabricating and operating fuel cells and electroconductive elements according to the present invention are also contemplated.

Abstract: Method and apparatus for cooling a fuel cell stack. The cooling system uses vaporization cooling of the fuel stack and supersonic vapor compression of the vaporized coolant to significantly increase the temperature and pressure of the liquid coolant flowing through a heat exchanger. By increasing the heat rejection temperature of the coolant delivered to the heat exchanger, the heat transfer area of the heat exchanger can be reduced and the mass flow rate of coolant can also be reduced. The increased fluid pressure is used to circulate the coolant through the cooling system, thereby eliminating the circulation pump associated with conventional systems.

Abstract: There is provided a multilayer gas distribution structure for use with a membrane electrode assembly of a PEM fuel cell. The layers of the multilayer diffusion structure have selected chemical and physical properties. Together, the layers facilitate transport of reactant gas to the electrode while improving water management.