The invention relates to a bipolar plate (10) for a fuel cell stack. The bipolar plate (10) respectively has two profiled separator plates (12, 14) respectively having an active area (16) and two distribution areas (18, 20) for supplying and discharging reaction gases and coolant to or from the active area (16), wherein the separator plates (12, 14) are designed and arranged on top of each other such that the respective bipolar plate (10) has separate channels (28, 30, 32) for the reaction gases and the coolant, which channels connect ports (22, 24, 26) for reaction gases and coolant of both distribution areas (18, 20) to each other. In the mounted fuel cell stack, the channels (28, 30) for the reaction gases are respectively bordered by a surface of a separator plate (12, 14) and a surface of a gas diffusion layer (58).
It is provided that the bipolar plate (10) have an impermeable first dividing plate (38), which respectively divides the channels (28) for a reaction gas in an inlet area (40) of the active area (16) into two volume areas and extends in the flow direction (42) of the reaction gas, wherein only one volume area of the channel (28) is adjacent to the gas diffusion layer (58).
The subject matter of the invention is also a fuel cell stack with such bipolar plates (10), as well as a fuel cell system with a fuel cell stack according to the invention.