NOVELTY - The module a set of structural plates (10a, 10b) arranged in face-to-face juxtaposition between opposite end pressure plates. The structural plates define a gas-liquid flow passage (21a) and a degassed liquid flow passage (22a) for fluid flow inside the module when the structural plates are in face-to-face juxtaposition. One of the plates defines holding features (50) for locating and holding a part of internal reinforcing parts when the plates are in face-to-face juxtaposition with one of other structural plate, end pressure plate and intermediate pressure plate.    USE - Internally-reinforced electrolyser module e.g. alkaline water electrolyser module and polymer electrolyte membrane type water electrolyser module, for production of hydrogen and oxygen gases at high pressure for a hybrid hydrogen vehicle.    ADVANTAGE - The structural plates are arranged adjacent to the end pressure plates or the intermediate pressure plates, so that the structural plates can be directly and mechanically reinforced by embedding into the adjacent end pressure plates or the adjacent intermediate pressure plates without utilizing the internal reinforcing parts, thus improving performance and lifetime of the module in a cost-effective manner.    DETAILED DESCRIPTION - The structural plates are made of plastic material or fiber-reinforced plastic material that is selected from one of polysulfone, polyphenylene oxide, polyphenylene sulfide, polypropylene and polyoxymethylene. The internal reinforcing parts are made of metal, plated metal or polymer-coated metal, where the metal is selected from one of steel, stainless steel, aluminum, aluminum alloy, copper, copper alloy, titanium and titanium alloy. An INDEPENDENT CLAIM is also included for an electrolyser stack.    DESCRIPTION OF DRAWING(S) - The drawing shows an exploded isometric view of front faces and a back face of structural plates and internal reinforcing parts for an electrolyser module.    Structural plates (10a, 10b)    Degassing chambers (19a, 19b)    Gas-liquid flow passage (21a)    Degassed liquid flow passage (22a)    Holding features (50)