Abstract: A fuel cell stack has a plurality of fuel cells arranged in a row, each of them comprising a membrane separating the electrodes, with ports for the respective supply and drainage of a fuel and an oxidizer and with a tensioning device for pressing the fuel cells together, wherein the tensioning device is formed by a band and spring system having an integrated force transducer, the signal of which can be relayed to a controller for determining the moisture content based on the moisture-dependent swelling behavior of the membrane of each fuel cell. A fuel cell device with such a fuel cell stack as well as a motor vehicle having such a fuel cell device are also provided.

Abstract: The invention relates to a method for operating a motor vehicle system. A control device provides a basic mode, and establishes for the motor vehicle system a further operating mode that differs from the basic mode in that the further operating mode, compared to the basic mode, provides a predetermined additional operating function, and which further operating mode is currently blocked. The control device outputs media content containing at least one question about a topical context, wherein the media content is a quiz and/or asks the user for motor vehicle relevant data, and receives an input of information and checks this as to whether it meets a predefined match criterion that prescribes a match with a category of the topical context and/or an intended answer and is thus an answer to the at least one question from the output media content. The control device unblocks the blocked operating mode and thereby enables the additional operating function only if the predefined match criterion is met.

Abstract: The disclosure relates to a method for increasing a temperature of a vehicle interior of a vehicle from a low temperature value to an increased temperature value, wherein the vehicle has a fuel cell system with a fuel cell stack and a compressor connected with the fuel cell stack at the cathode side, comprising: drawing in cathode gas via the compressor, and compressing and heating the drawn-in cathode gas. At least a portion of a cathode gas mass flow of the heated cathode gas is directed into the vehicle interior, and the temperature of the vehicle interior is raised to the increased temperature value. Moreover, the disclosure relates to a vehicle for implementing the method.