Abstract: An electrochemical cell monitoring device, in particular an electrolysis cell, fuel cell and/or battery cell monitoring device having at least one display module, which includes at least one display element, which is provided in order to output at least one information item regarding at least one function parameter of an electrochemical cell in the form of electromagnetic radiation. The electrochemical cell monitoring device includes at least one optical sensor unit arranged in particular separately and spaced apart from the display module, which is provided in order to detect the electromagnetic radiation at least of the display element and from the detected electromagnetic radiation read out at least the information regarding the at least one function parameter of the electrochemical cell.

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 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).