Fuel cell plate flow field

Abstract

A method of manufacturing a fuel cell flow field plate is disclosed in which a generally even flow distribution across the flow field is provided. The method includes providing an inlet manifold in fluid communication with the flow field. The flow field includes multiple channels for which some of the channels receive restricted flow from the inlet manifold as compared to other channels. A relative pressure drop between the channels is altered with a pressure drop feature to encourage fluid flow from the inlet manifold to the channels with restricted flow, which results in a generally even flow distribution across the flow field.

1 . A method of manufacturing a fuel cell plate flow field having generally even flow distribution across the flow field, the method comprising the steps of:
 providing an inlet manifold in fluid communication with a flow field, the flow field having multiple channels including first and second channels with second channels receiving restricted fluid flow from the inlet manifold compared to first channels;   altering the relative pressure drop between the first channels and the second channels with a pressure drop feature; and   encouraging fluid flow from the inlet manifold to the second channels in response to the pressure drop feature to provide generally even flow distribution between the first channels and the second channels.   
     
     
         2 . The method according to  claim 1 , wherein providing step includes the inlet manifold having a first width and the flow field having a second width greater than the first width, and inlets to the flow field arranged across the second width. 
     
     
         3 . The method according to  claim 2 , wherein the providing step includes the first and second channels extending along a length, the first and second channels parallel with one another along the length. 
     
     
         4 . The method according to  claim 1 , wherein the providing step includes a lateral inlet passage fluidly interconnecting the first channels to one another, the lateral inlet passage fluidly interconnected to the inlet manifold by inlet passages, a lateral exhaust passage fluidly interconnecting the second channels to one another, the lateral exhaust passage in fluid communication with an exhaust manifold, the pressure drop feature provided by the first and second channels being dead-ended by respectively extending from the inlet and exhaust lateral passages to first and second terminal ends, the first and second terminal ends respectively near the exhaust and inlet lateral passages, the first and second channels arranged in alternating relationship with one another. 
     
     
         5 . The method according to  claim 1 , wherein the providing step includes a restricted flow area at inlets to the second channels, and the pressure drop feature includes a cross passage from the first channel near first channel inlets to the second channel beneath the restricted flow area. 
     
     
         6 . The method according to  claim 5 , wherein the cross passage extends at an angle relative to a length of the first channels and away from the restricted flow area to the second channels. 
     
     
         7 . The method according to  claim 1 , wherein the pressure drop feature includes shallow channel portions in the first channels providing a second channel depth that is less than a first channel depth of the second channels. 
     
     
         8 . A fuel cell comprising:
 a structure including a flow field having multiple channels each with an inlet end, and a header in fluid communication with the inlet ends, the header including a restricted flow region in which fluid flow is restricted to the inlet ends of a set of channels, and at least some of the channels having a pressure drop feature configured to increase fluid flow to the set of channels.   
     
     
         9 . The fuel cell according to  claim 8 , wherein the pressure drop feature includes a cross passage from first channels near first channel inlets to second channels beneath the restricted flow area. 
     
     
         10 . The fuel cell according to  claim 9 , wherein the cross passage extends at an angle relative to a length of the first channels and away from the restricted flow area to the second channels. 
     
     
         11 . The fuel cell according to  claim 9 , comprising an inlet manifold having a first width and the flow field having a second width greater than the first width, and inlets to the flow field arranged across the second width. 
     
     
         12 . The fuel cell according to  claim 11 , wherein the restricted flow region is arranged on either side of the flow field at the inlet ends, the channels extending along a length from the inlet header toward an exhaust header, the channels parallel with one another along the length. 
     
     
         13 . The fuel cell according to  claim 8 , wherein the pressure drop feature includes shallow channel portions in first channels providing a second channel depth that is less than a first channel depth of the second channels, the second channels arranged beneath the restricted flow area. 
     
     
         14 . A fuel cell comprising:
 a structure including a flow field having first and second sets of channels, each channel of the first set of channels extending from an inlet end to a first terminal end, the inlet ends fluidly interconnected with one another by a lateral inlet passage that is configured to receive fluid from an inlet manifold, each channel of the second set of channels extending from an exhaust end to a second terminal end, the exhaust ends fluidly interconnected with one another by an lateral exhaust passage that is configured to provide fluid to an exhaust manifold, the first and second channels in alternating relationship with one another with the first and second terminal ends arranged near the lateral exhaust and inlet passages, respectively.   
     
     
         15 . The fuel cell according to  claim 14 , wherein the structure includes the inlet manifold, the inlet manifold having a first width and the lateral inlet passage having a second width that is greater than the first width. 
     
     
         16 . The fuel cell according to  claim 14 , wherein the first and second sets of channels extend from their respective lateral passages to their respective terminal end along a length, the first and second sets of channels parallel with one another along the length. 
     
     
         17 . The fuel cell according to  claim 14 , wherein laterally spaced inlet passages fluidly interconnect the inlet manifold and the lateral inlet passage, the inlet passages misaligned with the channels of the first set of channels.