The invention relates to an electrolysis arrangement for the electrochemical production of hydrogen and oxygen from an alkaline electrolyte having anode and cathode separators for the separation of oxygen and hydrogen from the electrolyte, and an anode and cathode pipe system to circulate electrolyte between anode and cathode sections of an electrolysis stack of the electrolysis arrangement. Control valves and interconnections are configured so that dependent on an electrolyte flow rate passing first, second and third control valve, oxygen and hydrogen depleted electrolyte withdrawn from the separators can be supplied unmixed, partly mixed or fully mixed to the anode and cathode sections of the electrolysis stack to control hydrogen to oxygen and oxygen to hydrogen crossover in the electrolysis arrangement.

An object is to provide a methane synthesis device having as a whole a reduced size and a simplified configuration. A methane synthesis device 100 is composed of respective components from an end plate 2 at the leftmost side to an end plate 23 at the rightmost side and is compactly assembled by fastening plural bolts and nuts to bring these individual components into tightly contact with each other. The components may be divided into a Sabatier reaction unit of signs 3 to 9, a water electrolysis unit of signs 13 to 19, and other components. Hydrogen gas generated in the water electrolysis unit is mixed with carbon dioxide gas and supplied to the Sabatier reaction unit, and methane is synthesized in the Sabatier reaction unit. The size of the device is reduced as a whole and configuration is simplified by integrally stacking the water electrolysis unit, the Sabatier reaction unit, a carbon dioxide supplying unit, and a hydrogen gas supplying unit.

An object is to provide a methane synthesis device having as a whole a reduced size and a simplified configuration. A methane synthesis device 100 is composed of respective components from an end plate 2 at the leftmost side to an end plate 23 at the rightmost side and is compactly assembled by fastening plural bolts and nuts to bring these individual components into tightly contact with each other. The components may be divided into a Sabatier reaction unit of signs 3 to 9, a water electrolysis unit of signs 13 to 19, and other components. Hydrogen gas generated in the water electrolysis unit is mixed with carbon dioxide gas and supplied to the Sabatier reaction unit, and methane is synthesized in the Sabatier reaction unit. The size of the device is reduced as a whole and configuration is simplified by integrally stacking the water electrolysis unit, the Sabatier reaction unit, a carbon dioxide supplying unit, and a hydrogen gas supplying unit.

A metal support for an electrochemical element where the metal support includes a plate face, has a plate shape as a whole, and has a warping degree of 1.5×10.sup.−2 or less determined by calculating a least square value through the least squares method using at least three points in the plate face of the metal support, calculating a first difference between the least square value and a positive-side maximum displacement value on a positive side with respect to the least square value and a second difference between the least square value and a negative-side maximum displacement value on a negative side that is opposite to the positive side with respect to the least square value, and dividing the sum of the first difference and the second difference by a maximum length of the plate face of the metal support that passes through a center of gravity.

The invention relates to a bipolar plate assembly (1) for forming an electrolysis or fuel cell stack and to the use of a bipolar plate assembly and an electrolysis or fuel cell stack with a plurality of bipolar plate assemblies.

The invention relates to a bipolar plate assembly (1) for forming an electrolysis or fuel cell stack and to the use of a bipolar plate assembly and an electrolysis or fuel cell stack with a plurality of bipolar plate assemblies.

The invention relates to an electrolysis arrangement for the production of hydrogen and oxygen by alkaline electrolysis. The electrolysis arrangement includes a system configuration which enables to balance the lye concentrations between the anode and cathode section of the arrangement depending on the current density of the direct current supplied to the electrolysis stack of the electrolysis medium. At high current densities, hydrogen to oxygen crossover and oxygen to hydrogen crossover is low, which allows full mixing of electrolysis media to balance the concentration between anolyte and catholyte. At low current densities, hydrogen to oxygen crossover and oxygen to hydrogen crossover is high. Therefore, the electrolysis arrangement is configured so that the mixing of the electrolysis media is decreased in case a current density of a direct current supplied to the electrolysis stack is decreased.

The invention relates to an electrolysis arrangement for the production of hydrogen and oxygen by alkaline electrolysis. The electrolysis arrangement includes a system configuration which enables to balance the lye concentrations between the anode and cathode section of the arrangement depending on the current density of the direct current supplied to the electrolysis stack of the electrolysis medium. At high current densities, hydrogen to oxygen crossover and oxygen to hydrogen crossover is low, which allows full mixing of electrolysis media to balance the concentration between anolyte and catholyte. At low current densities, hydrogen to oxygen crossover and oxygen to hydrogen crossover is high. Therefore, the electrolysis arrangement is configured so that the mixing of the electrolysis media is decreased in case a current density of a direct current supplied to the electrolysis stack is decreased.

Systems and methods for separator plates, bipolar plates, stacks of plates, and electrochemical systems, comprising at least one through-opening for the passage of a fluid and a rim that delimits the through-opening. The rim having a curved course and a rectilinear course that adjoins the curved course. A bead arrangement extends around the curved course and the rectilinear course. An edge portion spans the bead arrangement and the rim, so that the bead arrangement is situated at a distance from the rim. A cutout formed in the curved course, so that a minimum distance of the bead arrangement from the rim is smaller in the curved course than in the rectilinear course.

An electrochemical compressor, including a first end plate, a second end plate, a voltage supply connected to the first end plate and second end plate, a plurality of membranes, where each membrane of the plurality of membranes has a substantially same impedance, and where each membrane of the plurality of membranes has a different thickness in a stacking direction, and a plurality of conductive bipolar plates, where the bipolar plates of the plurality of bipolar plates are arranged in contact with, and alternating in the stacking direction with, the membranes of the plurality of membranes, and where the membranes of the plurality of membranes and the bipolar plates of the plurality of bipolar plates are electrically connected in series between the first end plate and second end plate.