Fuel cell stack having bipolar plates, and fuel cell system
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.
1. A fuel cell stack comprising:
gas diffusion layers; and
bipolar plates, each bipolar plate including:
an impermeable first dividing plate; and
two profiled dividing plates, each profiled dividing plate having:
an active area,
two distribution areas, each distribution area including two main gas ports for supply and removal of reaction gases from the active area, and a coolant main port for supply of coolant to the active area and removal of coolant from the active area, and
a second main gas port provided in one of the two distribution areas, wherein:
the profiled dividing plates are formed and arranged one over the other such that the respective bipolar plate has separate channels for the reaction gases and the coolant that connect the main gas ports for the reaction gases and the coolant main port of the two distribution areas to each other,
the channels for the reaction gases in the active area are each bounded by a surface of one of the profiled dividing plates and a surface of the gas diffusion layer,
a first one of the channels for the reaction gas in an inlet area of the active area has the impermeable first dividing plate that separates and divides the first one of the channels for the reaction gas into two volume regions and extends in a flow direction, wherein only one volume region of the first one of the channels for the reaction gas is adjacent to the gas diffusion layer,
the second main gas port is provided next to a first one of the two main gas ports in the distribution area to supply the reaction gas to the first one of the channels,
one of the two volume regions that is adjacent to the gas diffusion layer is connected to the first one of the two main gas ports, and
a second one of the two volume regions that is not adjacent to the gas diffusion layer is connected to a second one of the two main gas ports.
2. The fuel cell stack according to claim 1 , further comprising a plurality of impermeable dividing plates that are arranged downstream of the impermeable first dividing plate in the first one of the channels, wherein the impermeable dividing plates are arranged to be spaced apart from each other.
3. The fuel cell stack according to claim 2 , wherein starting from the inlet area of the first one of the channels, each successive impermeable dividing plate after the impermeable first dividing plate has a lesser length than the respective preceding impermeable dividing plate.
4. The fuel cell stack according to claim 1 , wherein the impermeable first dividing plate runs parallel to the gas diffusion layer.
5. The fuel cell stack according to claim 1 , wherein the volume regions established by the impermeable first dividing plate are designed to permit an equal flow volume of reaction gas.
6. The fuel cell stack according to claim 1 , wherein the channels run in a straight line.
7. The fuel cell stack according to claim 1 , wherein a second one of the channels for reaction gases has an impermeable first dividing plate in the inlet area of the active area that separates and divides the second one of the channels into two volume regions and extends in the flow direction, wherein only one volume region of the second one of the channels is adjacent to the gas diffusion layer,
a second main gas port is provided next to a first one of two main gas ports in the distribution area to supply the reaction gas to the second one of the channels,
one of the two volume regions that is adjacent to the gas diffusion layer is connected to the first one of the two main gas ports, and
a second one of the two volume regions that is not adjacent to the gas diffusion layer is connected to a second one of the two main gas ports.
8. The fuel cell stack according to claim 1 , wherein the fuel cell stack includes polymer-electrolyte membranes.
9. A fuel cell system comprising:
a fuel cell stack, the fuel cell stack including:
gas diffusion layers; and
bipolar plates, each bipolar plate including:
an impermeable first dividing plate; and
two profiled dividing plates, each profiled dividing plate having:
an active area,
two distribution areas, each distribution area including two main gas ports for supply and removal of reaction gases from the active area, and a coolant main port for supply of coolant to the active area and removal of coolant from the active area, and
a second main gas port provided in one of the two distribution areas, wherein:
the profiled dividing plates are formed and arranged one over the other such that the respective bipolar plate has separate channels for the reaction gases and the coolant that connect the main gas ports for the reaction gases and the coolant main port of the two distribution areas to each other,
the channels for the reaction gases in the active area are each bounded by a surface of one of the profiled dividing plates and a surface of the gas diffusion layer,
a first one of the channels for the reaction gas in an inlet area of the active area has the impermeable first dividing plate that separates and divides the first one of the channels for the reaction gas into two volume regions and extends in a flow direction, wherein only one volume region of the first one of the channels for the reaction gas is adjacent to the gas diffusion layer,
the second main gas port is provided next to a first one of the two main gas ports in the distribution area to supply the reaction gas to the first one of the channels,
one of the two volume regions that is adjacent to the gas diffusion layer is connected to the first one of the two main gas ports, and
a second one of the two volume regions that is not adjacent to the gas diffusion layer is connected to a second one of the two main gas ports.
10. The fuel cell system according to claim 9 , comprising at least one humidifier that is configured to humidify a portion of at least one reaction gas.
11. The fuel cell system according to claim 9 , wherein the impermeable first dividing plate runs parallel to the gas diffusion layer.
12. The fuel cell system according to claim 9 , wherein the volume regions established by the impermeable first dividing plate are designed to permit an equal flow volume of reaction gas.
13. The fuel cell system according to claim 9 , wherein the channels run in a straight line.
14. The fuel cell system according to claim 9 , further comprising a plurality of impermeable dividing plates that are arranged downstream of the impermeable first dividing plate in the first one of the channels, wherein the impermeable dividing plates are arranged to be spaced apart from each other.
15. The fuel cell system according to claim 14 , wherein starting from the inlet area of the first one of the channels, each successive impermeable dividing plate after the impermeable first dividing plate has a lesser length than the respective preceding impermeable dividing plate.