Abstract: An electrochemical hydrogen compression system includes a hydrogen gas compression part that compresses hydrogen by applying a current between an anode and a cathode provided on two surfaces of a proton exchange film, and a supply pipeline that guides hydrogen discharged from a hydrogen supply source to the hydrogen gas compression part. The hydrogen gas compression part has an outlet for discharging unreacted hydrogen. The electrochemical hydrogen compression system further includes a film resistance meter and a voltmeter that acquire information related to a wet state of the proton exchange film, a fourth opening/closing part and a fifth opening/closing part that regulate discharge of hydrogen from the outlet, and a control device that controls the fourth opening/closing part and the fifth opening/closing part. The control device controls the fourth opening/closing part and the fifth opening/closing part based on at least the wet state of the proton exchange film.

Abstract: An electrochemical hydrogen compression system includes a hydrogen gas compression part that compresses hydrogen by applying a current between an anode and a cathode provided on two surfaces of a proton exchange film, and a supply pipeline that guides hydrogen discharged from a hydrogen supply source to the hydrogen gas compression part. The hydrogen gas compression part has an outlet for discharging unreacted hydrogen. The electrochemical hydrogen compression system further includes a film resistance meter and a voltmeter that acquire information related to a wet state of the proton exchange film, a fourth opening/closing part and a fifth opening/closing part that regulate discharge of hydrogen from the outlet, and a control device that controls the fourth opening/closing part and the fifth opening/closing part. The control device controls the fourth opening/closing part and the fifth opening/closing part based on at least the wet state of the proton exchange film.

Abstract: A differential pressure water electrolysis system includes high-pressure water electrolysis cells, first and second end plates, and a high pressure hydrogen manifold. The high pressure hydrogen manifold is provided to distribute hydrogen in a stacking direction. Each of the high-pressure water electrolysis cells includes an electrolyte membrane, an anode current collector, a cathode current collector, an anode separator, a cathode separator, an elastic member, a manifold member, and a cylindrical porous member. The manifold member is disposed between the anode separator and the electrolyte membrane to surround the high pressure hydrogen manifold and includes a seal chamber in which a sealing member is disposed to encircle and seal the high pressure hydrogen manifold. The cylindrical porous member is disposed in the manifold member between the seal chamber and the high pressure hydrogen manifold.

Abstract: A differential pressure water electrolysis system includes high-pressure water electrolysis cells and a high pressure hydrogen manifold. The high-pressure water electrolysis cells are stacked in a stacking direction. Each of the high-pressure water electrolysis cells includes an electrolyte membrane, an anode current collector, a cathode current collector, a tabular anode separator, a tabular cathode separator, a sealing member, and a resin frame member. The resin frame member is disposed between the tabular anode separator and the tabular cathode separator so as to surround the sealing member and the anode current collector. The resin frame member includes a water supply port to introduce water for electrolysis and a water discharge port to discharge a surplus of the water after electrolysis. The high pressure hydrogen manifold is provided so as to distribute hydrogen in the stacking direction and so as to be encircled by the sealing member.

Abstract: A pressure releasing method in a water electrolysis system including a water electrolyzer, the pressure releasing method includes operating the water electrolyzer to electrolyze water to produce oxygen with a first pressure on an anode side and hydrogen with a second pressure higher than the first pressure on the cathode side. It is determined whether the water electrolyzer is in a frozen environment when the water electrolysis system stops operating. The cathode side is depressurized without suppling a depressurizing current to the water electrolyzer if it is determined that the water electrolyzer is in the frozen environment, or with suppling the depressurizing current to the water electrolyzer if it is determined that the water electrolyzer is not in the frozen environment.

Abstract: A starting method includes determining whether a depressurizing current was supplied to a water electrolyzer while at least a cathode side of the water electrolyzer was depressurized in an immediately previous stop of a water electrolysis system after electrolyzing water. A first current is supplied to the water electrolyzer at a first supply rate to start the water electrolysis system in a case where it is determined that the depressurizing current was supplied to the water electrolyzer in the immediately previous stop. A second current is supplied to the water electrolyzer at a second supply rate lower than the first supply rate to start the water electrolysis system in a case where it is determined that the depressurizing current was not supplied to the water electrolyzer in the immediately previous stop.

Abstract: A differential pressure water electrolysis system includes high-pressure water electrolysis cells and a high pressure hydrogen manifold. The high-pressure water electrolysis cells are stacked in a stacking direction. Each of the high-pressure water electrolysis cells includes an electrolyte membrane, an anode current collector, a cathode current collector, a tabular anode separator, a tabular cathode separator, a sealing member, and a resin frame member. The resin frame member is disposed between the tabular anode separator and the tabular cathode separator so as to surround the sealing member and the anode current collector. The resin frame member includes a water supply port to introduce water for electrolysis and a water discharge port to discharge a surplus of the water after electrolysis. The high pressure hydrogen manifold is provided so as to distribute hydrogen in the stacking direction and so as to be encircled by the sealing member.

Abstract: A differential pressure water electrolysis system includes high-pressure water electrolysis cells, first and second end plates, and a high pressure hydrogen manifold. The high pressure hydrogen manifold is provided to distribute hydrogen in a stacking direction. Each of the high-pressure water electrolysis cells includes an electrolyte membrane, an anode current collector, a cathode current collector, an anode separator, a cathode separator, an elastic member, a manifold member, and a cylindrical porous member. The manifold member is disposed between the anode separator and the electrolyte membrane to surround the high pressure hydrogen manifold and includes a seal chamber in which a sealing member is disposed to encircle and seal the high pressure hydrogen manifold. The cylindrical porous member is disposed in the manifold member between the seal chamber and the high pressure hydrogen manifold.