Energy-converting fuel cell or electrolyzer

The invention relates to a device (1) for Converting chemical energy into electrical energy, or electrical energy into chemical energy, having at least one electrochemically active, planar cell (2) that is held securely between coaxial annular disks (10a, 10b, 10c, 10d) of an electrically insulating support frame (10), through which a supply structure with Channels (22, 23, 13, 33) for process media extends to the cell (2). A free spatial region (8a, 8b) is present on either side of the cell (2) in the axial direction, which region is bounded in the radial direction by at least one of the annular disks (10a, 10b). The spatial regions (8a, 8b) are open toward a pressure Chamber (5) via at least one passage (42a, 42b) through the corresponding annular disk (10a, 10b). When the device (1) is in Operation, the pressure Chamber (5) is filled with a pressurized medium, as a consequence of which the cells are compressed. In this manner, the device (1) according to the invention combines the advantages of a conventional Stack of cells (2, 2′) with a hydraulic or pneumatic compression.