The invention relates to a fuel cell stack having bipolar plates (10), each of which has two separator plates (12, 14) with an active region (16) and two distribution regions (18, 20) with main gas ports (22, 24) as well as a coolant main port (26), wherein the separator plates (12, 14) are formed and arranged one over the other in such a way that the respective bipolar plate (10) has separate channels (28, 30, 32) for the reaction gases and the coolant that connect the main gas port (22, 24) for the reaction gases and the coolant main port (26) of the two distribution region (18, 20) to each other.It is provided that the channels (28) for a reaction gas have an impermeable first dividing plate (38) in an inlet area (40) of the active area (16) that separates the channels (28) into two volume areas (58, 60), and in that a second main gas port (23) is provided adjacent to the first main gas port (22) in a distribution region (18) in order to supply the reaction gas.The subject matter of the invention is also a fuel cell system that has a fuel cell stack according to the invention.