NOVELTY - The bipolar plate for a proton exchange membrane (PEM) electrolyzer for the electrolysis of water, comprises a central area that has a flow field (3) reciprocally at the surface with channels (4), an end area enclosing the central area, and an inlet (5) and an outlet for the flow field arranged in the end area. The central area is area-wisely formed in an electrically conductive manner so that a current flow is provided from the flow field to the flow field (3') present on other side. The bipolar plate is formed from a base material. The central area comprises a conducting element.    USE - Bipolar plate for a proton exchange membrane (PEM) electrolyzer for the electrolysis of water and/or for a fuel cell (all claimed).    ADVANTAGE - The bipolar plate can be simply and economically manufactured.    DETAILED DESCRIPTION - The bipolar plate for a proton exchange membrane (PEM) electrolyzer for the electrolysis of water, comprises a central area that has a flow field (3) reciprocally at the surface with channels (4), an end area enclosing the central area, and an inlet (5) and an outlet for the flow field arranged in the end area. The central area is area-wisely formed in an electrically conductive manner so that a current flow is provided from the flow field to the flow field (3') present on other side. The bipolar plate is formed from a base material. The central area comprises a conducting element. The bipolar plate is producible by a press fit of the conductive element in the central area and by spray-casting of the conductive element with the base material. The conductive element is sealed by an O-ring (25a, 25b) and consists of a contact pin (2) and/or a shaped-metal sheet. The metal sheet is formed in a shape of a repetitive trapezoid or corrugated sheet. The central area or the total bipolar plate is partially formed from a conductive polymer. The bipolar plate contains fillers, corrosion resistant metallic powders or fibers, reinforcement materials, glass fibers, antioxidants and/or pigments. The central area comprises a recess on both sides. The end area comprises a sealing groove for receiving an O-ring sealing on a side, and guiding holes for the admission of threaded rods. A polymer seal directly applied by two-component injection molding is arranged in the end area.    DESCRIPTION OF DRAWING(S) - The diagram shows a bipolar plate for a proton exchange membrane electrolyzer.    Contact pin (2)    Flow field (3, 3')    Channels (4)    Inlet (5)    O-ring. (25a, 25b)