NOVELTY - The module (100) has the structural plates (10a-10d) that are arranged in face to face juxtaposition between opposite end pressure plates (11). A half cell chamber opening (20a) partially houses electrolytic half cell components. A bipolar plate (17) communicates with electrode. A membrane (15) communicates with electrode for providing ionic conduction. The structural plates define the passages (21a,21b,22a,22b) for fluid flow inside module in face-to-face juxtaposition. One of structural plates defines contacting portion (50) for contacting with reinforcing unit.    USE - Electrolyzer module such as alkaline electrolyzer module and polymer electrolyte membrane (PEM) electrolyzer module for production of hydrogen and oxygen gases at elevated pressure through electrochemical reaction in hydrogen vehicles and equipment powered by hydrogen fuel cell engine or hydrogen internal combustion engine.    ADVANTAGE - Since the contacting portion of the external reinforcing unit can be machined directly into the main housing, or into a support plate and attached to the main housing and the teeth are angled to provide contact in multiple directions and provide multi-directional support and strength, the external reinforcing unit can mitigate outward displacement of the plastic structural plate material in response to fluid pressure within the electrolyser module so as to achieve stress relief in the middle sections of the structural plate. Thus, the external reinforcing unit can reduce the amount of plastic material used around the periphery of the structural plates which in turn allows the electrolyzer module to be easily installed and reduces the cost, size and weight of electrolyzer module, and shot size for injection molding while improving the creep resistance and structural plate lifetime.    DESCRIPTION OF DRAWING(S) - The drawing shows an exploded view of the alkaline electrolyzer module.    Structural plates (10a-10d)    End pressure plate (11)    Membrane (15)    Bipolar plate (17)    Half cell chamber opening (20a)    Passages (21a,21b,22a,22b)    Contacting portion (50)    Electrolyzer module (100)