Abstract: A water electrolysis system includes a high-pressure water electrolysis apparatus and a gas-liquid separation device. The gas-liquid separation device includes a block member which includes a gas-liquid separation opening and a water-level detection opening. The gas-liquid separation opening and the water-level detection opening extend substantially vertically and includes respective bottom portions which integrally communicate with a discharge pipe. The discharge pipe is disposed at a lower side portion of the block member. The water-level detection opening includes a top portion and a top water-level detection section. The block member further includes an inlet hole in which the hydrogen is introduced from the high-pressure water electrolysis device. The inlet hole is disposed at an upper side portion of the block member. The inlet hole is positioned above the top water-level detection section of the water-level detection opening.

Abstract: A high-pressure hydrogen producing apparatus includes a first cell device and a second cell device. The first cell device includes an electrolyte membrane, an anode electrode catalyst layer and an anode current collector provided on a first surface of the electrolyte membrane, and a cathode electrode catalyst layer and a cathode current collector provided on a second surface of the electrolyte membrane. The second cell device includes an electrolyte membrane, an anode current collector provided on a first surface of the electrolyte membrane of the second cell device, and a cathode current collector provided on a second surface of the electrolyte membrane of the second cell device.

Abstract: A controller (control portion) of a fuel cell system is provided with a flow path switching control device that switches a thermostat valve (flow path switching valve) so that, after a fuel cell has stopped generating electric power, coolant is supplied to a radiator circulation path until the coolant temperature becomes a second temperature threshold value that is lower than a first temperature threshold value.

Abstract: A hydrogen generating system is equipped with a water electrolysis unit for producing hydrogen by performing electrolysis on pure water supplied from a pure water supply apparatus, with a back-pressure valve mechanism disposed in a hydrogen outlet port of the water electrolysis unit. The back-pressure valve mechanism is equipped with a first back-pressure valve, which sets a first back pressure, for discharging hydrogen to the outside of a hydrogen supply passage, and a second back-pressure valve, which sets a second back pressure at a higher pressure than the first back pressure, for extracting high-pressure hydrogen into the hydrogen supply passage.

Abstract: In a unit cell that forms a water electrolysis device, which is an electrochemical device, an electrolyte membrane/electrode structure is sandwiched between an anode-side separator and a cathode-side separator. A load-applying mechanism is disposed between a cathode-side feeder and the cathode-side separator, while an anode-side feeder is set with a smaller contact area range than the aforementioned cathode-side feeder. The anode-side feeder and the cathode-side feeder are set with a larger contact area range than an anode electrode catalyst layer and a cathode electrode catalyst layer, and a contact surface that touches a solid polymer electrolyte membrane on the aforementioned anode-side feeder is disposed projecting farther to the side of the aforementioned solid polymer electrolyte membrane than a contact surface on the anode-side separator and a contact surface on a frame member.

Abstract: A water electrolysis system includes a water electrolysis apparatus for electrolyzing pure water supplied from a pure water supply apparatus to produce high-pressure hydrogen. A pressure releasing device is connected between a pipe of the water electrolysis apparatus and a check valve connected to the inlet port of a gas-liquid separator, for releasing the pressure of the high-pressure hydrogen from the water electrolysis apparatus independently from the gas-liquid separator. The pressure releasing device has a bleeder passage including a pressure reducing valve and a solenoid-operated valve.

Abstract: A high-pressure hydrogen producing apparatus includes a first cell device and a second cell device. The first cell device includes an electrolyte membrane, an anode electrode catalyst layer and an anode current collector provided on a first surface of the electrolyte membrane, and a cathode electrode catalyst layer and a cathode current collector provided on a second surface of the electrolyte membrane. The second cell device includes an electrolyte membrane, an anode current collector provided on a first surface of the electrolyte membrane of the second cell device, and a cathode current collector provided on a second surface of the electrolyte membrane of the second cell device.

Abstract: A water electrolysis system includes a high-pressure water electrolysis apparatus and a gas-liquid separation device. The gas-liquid separation device includes a block member which includes a gas-liquid separation opening and a water-level detection opening. The gas-liquid separation opening and the water-level detection opening extend substantially vertically and includes respective bottom portions which integrally communicate with a discharge pipe. The discharge pipe is disposed at a lower side portion of the block member. The water-level detection opening includes a top portion and a top water-level detection section. The block member further includes an inlet hole in which the hydrogen is introduced from the high-pressure water electrolysis device. The inlet hole is disposed at an upper side portion of the block member. The inlet hole is positioned above the top water-level detection section of the water-level detection opening.

Abstract: Each unit cell of a water electrolysis apparatus includes a pair of an anode separator and a cathode separator and a membrane electrode assembly interposed between the pair of separators. The anode separator has a first flow field to which water is supplied, and the cathode separator has a second flow field for producing high-pressure hydrogen through electrolysis of the water. A second seal groove for receiving a second seal member is disposed annularly around the second flow field. A pressure-releasing chamber is disposed outwardly of the second seal groove, is capable of communicating with the second seal groove and communicates with the outside through a depressurizing channel.

Abstract: A method for operating a water electrolysis system includes determining whether or not a water electrolysis apparatus is shut down. The water electrolysis system includes the water electrolysis apparatus, a water circulation apparatus, and a gas-liquid separation apparatus. The water electrolysis apparatus includes power feeders provided on an anode side and a cathode side of an electrolyte membrane. The water electrolysis apparatus generates oxygen on the anode side and generates hydrogen on the cathode side at a higher pressure than a pressure of the oxygen by electrolysis of water. Pressure on the cathode side is released when it is determined that the water electrolysis apparatus is shut down. The water circulation apparatus is operated until a concentration of hydrogen remaining on the anode side is a specified value or less under a condition in which a release of pressure on the cathode side is completed.

Abstract: Each unit cell of a water electrolysis apparatus includes a pair of an anode separator and a cathode separator and a membrane electrode assembly interposed between the pair of separators. The anode separator has a first seal groove extending annularly around an anode current collector, a first seal member being disposed in the first seal groove. The cathode separator has a second seal groove extending annularly around a cathode current collector, a second seal member being disposed in the second seal groove. The first seal groove and the second seal groove are located across the solid polymer electrolyte membrane from each other respectively at different positions with respect to a stacking direction of the separators.

Abstract: A water electrolysis apparatus is formed by stacking a plurality of unit cells. Each unit cell includes a membrane electrode assembly, and an anode separator and a cathode separator which sandwich the membrane electrode assembly therebetween. The anode separator has a plurality of inlet joint channels in fluid communication with a water supply passage, and a plurality of outlet joint channels in fluid communication with a discharge passage. The water supply passage has an inner wall surface at which the inlet joint channels are open, and an outer wall surface which faces the inner wall surface, the inner wall surface and the outer wall surface jointly forming an opening of an oblong cross-sectional shape.

Abstract: A water electrolysis apparatus includes an anode separator having a water flow field held in fluid communication with a water supply passage and a discharge passage. The water flow field includes a plurality of water channels, an arcuate inlet buffer, and an arcuate outlet buffer. The water channels have respective ends connected to the arcuate inlet buffer through respective inlet joint channels. The inlet joint channels are oriented at an angle of 90 degrees or greater with respect to respective tangential lines at the ends of the inlet joint channels which are connected to the arcuate inlet buffer.

Abstract: A water electrolysis apparatus includes a plurality of unit cells. A membrane electrode assembly of the unit cell includes an anode side power feeding element and a cathode side power feeding element stacked on an anode catalyst layer and a cathode catalyst layer on both surfaces of a solid polymer electrolyte membrane. A surface of the anode side power feeding element is subjected to a grinding process, and then, subjected to an etching process to form a smooth surface.

Abstract: The invention provides a high-pressure hydrogen production apparatus for preventing hydrogen gas from leaking toward an anode side and for obtaining excellent electrolytic efficiency. The apparatus includes a single cell having a solid polymer electrolyte membrane, power feeders, separators, and fluid channels provided in respective separators. High-pressure hydrogen gas accompanied by water is obtained in the fluid channel by supplying water to the fluid channel and applying current to each power feeder to electrolyze water. The obtained hydrogen gas and water are subjected to gas-liquid separation in a second compartment of a high-pressure vessel, and hydrogen gas thus separated is used to press a barrier member towards the single cell. The separated water is supplied to the fluid channel through the hydrogen gas guide channel.

Abstract: A water electrolysis system has a water electrolysis apparatus for electrolyzing pure water, thereby producing hydrogen, a water storage apparatus for separating between oxygen and residual water discharged from the water electrolysis apparatus, thereby storing the water, a water circulation apparatus for circulating the water stored in the water storage apparatus through the water electrolysis apparatus, and a water supply apparatus for supplying the pure water prepared from city water to the water storage apparatus. An inlet is formed at one end of a return pipe to introduce the oxygen and the residual water discharged from the water electrolysis apparatus into a tank, and the position of the inlet is determined such that the inlet is constantly opened in the water stored in the tank.

Abstract: A water electrolysis apparatus applies an electrolysis voltage between current collectors disposed on the respective sides of an electrolyte membrane thereby to electrolyze water to generate oxygen in an anode electrolysis chamber and hydrogen in a cathode electrolysis chamber under a pressure higher than a normal pressure. The water electrolysis apparatus is shut down by applying a voltage between the current collectors after the cathode electrolysis chamber stops supplying the hydrogen, reducing a pressure in at least the cathode electrolysis chamber while the voltage is being applied, and stopping applying the voltage when the pressure in the cathode electrolysis chamber is equal to a pressure in the anode electrolysis chamber.

Abstract: A water electrolysis system includes a water electrolysis apparatus for electrolyzing pure water supplied from a pure water supply apparatus for manufacturing high-pressure hydrogen. The water electrolysis apparatus has a pipe serving as a hydrogen outlet to which a gas-liquid separator, a cooler, and a water adsorption apparatus are successively connected in this order along the direction in which hydrogen is discharged from the water electrolysis apparatus. A first back-pressure valve is connected between the cooler and the water adsorption apparatus, and a second back-pressure valve is connected downstream of the water adsorption apparatus.

Abstract: A water electrolysis system includes a water electrolysis apparatus for electrolyzing pure water supplied from a pure water supply apparatus to produce high-pressure hydrogen. A pressure releasing device is connected between a pipe of the water electrolysis apparatus and a check valve connected to the inlet port of a gas-liquid separator, for releasing the pressure of the high-pressure hydrogen from the water electrolysis apparatus independently from the gas-liquid separator. The pressure releasing device has a bleeder passage including a pressure reducing valve and a solenoid-operated valve.

Abstract: A hydrogen generating system is equipped with a water electrolysis unit for producing hydrogen by performing electrolysis on pure water supplied from a pure water supply apparatus, with a back-pressure valve mechanism disposed in a hydrogen outlet port of the water electrolysis unit. The back-pressure valve mechanism is equipped with a first back-pressure valve, which sets a first back pressure, for discharging hydrogen to the outside of a hydrogen supply passage, and a second back-pressure valve, which sets a second back pressure at a higher pressure than the first back pressure, for extracting high-pressure hydrogen into the hydrogen supply passage.