Abstract: A method for operating an electrolysis device (2) for producing hydrogen uses a water circuit. Water from a polymer electrolyte membrane (PEM) electrolyzer (6) is cooled in a cooling device (10) and subsequently led to an ion exchanger (4) for processing the water. The water, after the processing in the ion exchanger (4), is fed to the PEM electrolyzer (6). Heat is removed from the water before feeding the water to the cooling device (10). A part of this removed heat is fed again to the water after the processing in the ion exchanger (4) and before entry into the PEM electrolyzer (6).

Abstract: A method is provided for running up/starting up an electrolysis device (10), which device includes a reactor container (3) which is arranged downstream of an electrolyzer (1) and in which oxygen reacts with hydrogen into water, in order to reduce an oxygen share in a hydrogen gas flow coming from the electrolyzer (1). The electrolysis device (10) is operated with a predefined operating pressure. Upon running up/starting up the electrolyzer (1), the hydrogen gas flow coming from the electrolyzer (1) is led past the reactor container (3) via a bypass conduit (11).

Abstract: A method for operating an electrolysis device (2) for producing hydrogen uses a water circuit. Water from a polymer electrolyte membrane (PEM) electrolyzer (6) is cooled in a cooling device (10) and subsequently led to an ion exchanger (4) for processing the water. The water, after the processing in the ion exchanger (4), is fed to the PEM electrolyzer (6). Heat is removed from the water before feeding the water to the cooling device (10). A part of this removed heat is fed again to the water after the processing in the ion exchanger (4) and before entry into the PEM electrolyzer (6).

Abstract: An electrolysis device (7) includes a water circuit (6), in which an electrolyzer (5), a collection container (1) and at least one pump (2) are arranged. The water is pumped by way of the at least one pump (2) out of the collection container (1) to the electrolyzer (5). The water circuit (6) is branched into at least one first branch (8) and into a second branch (9) which is parallel to the first branch (8). The electrolyzer (5) is arranged in the first branch (8) and a heat exchanger (3), for cooling the water, is arranged in the second branch (9).

Abstract: An electrolyzer (2) includes at least one electrolysis cell (4), arranged between two end plates (6.8), in a polymer electrolyte membrane construction manner, and a pressing device for producing a pressing force between the end plates (6.8). The pressing force at least partly is controlled in a manner dependent on the gas pressure produced by the electrolysis cell (4).

Abstract: A method is provided for running up/starting up an electrolysis device (10), which device includes a reactor container (3) which is arranged downstream of an electrolyzer (1) and in which oxygen reacts with hydrogen into water, in order to reduce an oxygen share in a hydrogen gas flow coming from the electrolyzer (1). The electrolysis device (10) is operated with a predefined operating pressure. Upon running up/starting up the electrolyzer (1), the hydrogen gas flow coming from the electrolyzer (1) is led past the reactor container (3) via a bypass conduit (11).

Abstract: An apparatus for the electrical production of hydrogen from water includes an electrolyzer (1) of the PEM type. The electrolyzer (1) has an inlet (2) for the introduction of water and a first outlet (3) for the hydrogen which is enriched with water and/or water vapor and is produced in the electrolyzer (1) and also a second outlet (4) for oxygen. A water separation device (7) which has at least a thermal separation stage (10) adjoins the electrolyzer (1).

Abstract: A fuel cell stack comprising several superimposed polymer electrolyte membrane fuel cells. A bipolar plate that is provided with longitudinal ducts supplying hydrogen and transverse ducts which supply oxygen and are used for cooling is arranged between adjacent membrane-electrode units. A current flowing in opposite directions through adjacent ducts of the same fuel cell can be created within the air ducts via collecting ducts that are provided at the outflow end for every other cooling duct if the flow is fed to the stack from both sides, resulting in a very homogeneous temperature distribution with the cell or stack.

Abstract: The end-plate assembly clamps an electrochemical cell or a stack of electrochemical cells with a polymer electrolyte membrane construction, in addition to forming the contact. An end plate (1) consisting of a synthetic material or metal, which is used to introduce the compressive forces into the cells or the cell stack, is provided. The end plate (1) is provided with a compensation layer (5) in the vicinity of the cell, which evens out the force introduction into the cell or the stack over the surface. The compensation layer (5) is covered with an electrically conductive layer (6), in order to form the electric connection (7) to the cell. The electrically conductive layer (6) is coupled to a connection (7) that is externally accessible.