Water electrolysis single-pile device and water electrolysis tank

The invention relates to a water electrolysis single-pile device and a water electrolysis tank. The single-pile device comprises a cathode gas diffusion layer, a proton exchange membrane assembly, an anode gas diffusion layer, a cathode collector plate and an anode collector plate, the cathode gas diffusion layer, the proton exchange membrane assembly and the anode gas diffusion layer are all cylindrical hollow structures, and are coaxially sleeved and assembled in a contact manner from inside to outside in sequence in an insertion manner; the cathode gas diffusion layer and the anode gas diffusion layer are both of conductive breathable structures, the cathode collector plate is electrically connected with the cathode gas diffusion layer, and the anode collector plate is electrically connected with the anode gas diffusion layer; the inner side of the cathode gas diffusion layer is vacant and is not provided with a polar plate, a hydrogen channel for discharging hydrogen is formed, and the hydrogen can be dis