Arrangement and method for determining hydrogen purity

A device for determining a purity of hydrogen, comprising:

• a measurement fuel cell cascade comprising a plurality of series-connected fuel cells and being connected to one another via a hydrogen line, a hydrogen inlet and a hydrogen outlet, wherein at least one measurement fuel cell is a first fuel cell in the measurement fuel cell cascade with respect to a flow direction of the hydrogen,
• a cell voltage monitoring unit, which is electrically connected to the at least one measurement fuel cell and monitors a voltage output of the at least one measurement fuel cell,
• a valve arranged downstream of the measurement fuel cell cascade in the flow direction of the hydrogen for allowing dead-end operation of the measurement fuel cell cascade,
• an evaluation unit, which is connected to the cell voltage monitoring unit and receives a signal corresponding to the voltage output of the at least one measurement fuel cell as a function of time from the cell voltage monitoring unit,
• wherein the evaluation unit comprises a microprocessor configured to compare the signal corresponding to the voltage output of the at least one measurement fuel cell with a library of stored voltage outputs to determine the purity of the hydrogen.