Electrolysis device

The invention relates to an electrolysis device, comprising at least one horizontal electrolytic cell with a housing (6) and an anode (8) that has a membrane or a diaphragm (18), and a cathode (9) that has a gas diffusion electrode (17). The device further comprises supply (21) and discharge (23) means for gas (3) which lead to or away from the gas chamber (22) of the cathode (9), and supply (16; 19) and discharge (16; 20) means for electrolytes (1) which lead to or away from the first electrolytic chamber (4) and to or away from the second electrolytic chamber (5). The anode (8) and the membrane or the diaphragm (18) have at least one respective opening for the supply (19) of electrolytes (1) to the second electrolytic chamber (5), and at least one one further opening for the discharge (20) of electrolytes from the second electrolytic chamber.