Abstract:
A fuel cell has cell units and a manifold for uniformly supplying an anode fluid to the cell units. The manifold has a fluid supply plate with a flow conduit for feeding an anode fluid, and a plate structure having a flow space and openings arranged in a preselected direction. The flow space receives an anode fluid fed from an opening part of the flow conduit, reduces a flow rate of the anode fluid, and disperses the anode fluid at the reduced flow rate along a plane direction orthogonal to the preselected direction. The block group is arranged between the openings and the opening part so that the flow space is disposed between the block group and the opening part. The block group comprises blocks spaced apart from one another to form paths for dispersing into the openings the anode fluid dispersed by the flow space at the reduced rate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. national stage application of International Application No. PCT/JP2008/062027 filed Jul. 3, 2008, claiming a priority date of Jul. 10, 2007, and published in a non-English language. 
     BACKGROUND OF THE INVENTION 
     Technical Field 
     The present invention relates to a fuel cell that feeds an anode fluid from a manifold to each cell unit of a cell stack. 
     BACKGROUND OF THE INVENTION 
     Due to the upsurge of recent energy issues, an electric source with a higher energy density and with cleaner discharge has been demanded. A fuel cell is a generator with an energy density several fold those of existing batteries. A fuel cell has characteristic features of higher energy efficiency and little or no nitrogen oxides or sulfur oxides in discharged gases. Therefore, a fuel cell is an extremely effective device satisfying the demand as a next-generation electric source device. 
     The cell of a fuel cell comprises an anode-side catalyst (anode) and a cathode-side catalyst (cathode) on both the sides of the solid polymer electrolyte membrane as an electrolyte membrane. By alternately arranging a separator with an anode fluid path and a cathode fluid path formed thereon while these paths sit back to back and the cell, a cell unit is formed. By stacking a plurality of such cell units together, then, a cell stack is constructed. A fuel cell of such stack structure is equipped with a manifold for uniformly dividing a fuel to each of the cell units to uniformly feed the fuel in the cell stack, so as to feed the fuel from the manifold to each of the cell units. 
     When the fuel is fed non-uniformly to each of the cell units in the cell stack, the output from each of the cell units varies, leading to the reduction of the power generation, so that the output from the whole cell stack is affected by the output from a low-output cell unit. Therefore, it is demanded that such manifold should have a uniform division performance at a higher dimension for the fuel supply to each of the cell units in the cell stack. 
     In such circumstances, various techniques for uniformly feeding a fuel to each of the cell units in a cell stack have been proposed (the publication of JP-A-Hei 9-161828). For fuel supply, in the publication, the manifold is constructed with a second space for dispersion, which is arranged adjacent to the cell stack, and a first space where a hydrogen rich gas is fed. The hydrogen rich gas fed in the first space is transferred through a through hole to the second space, where the hydrogen rich gas is dispersed and fed to each of the cell units. 
     Because the hydrogen rich gas is dispersed in the second space, the variation in the feed volume between cell units close to the through hole and cell units remote from the through hole is reduced, so that the hydrogen rich gas can be fed uniformly to all the cell units in the cell stack. 
     Patent reference 1: JP-A-Hei 9-161828 
     Because the hydrogen rich gas is necessarily dispersed in the second space according to the conventional technique, it was required to make the ratio of the volume of the second space to the whole volume of the first space and the second space larger. Unless the distance from the through hole to the cell units is at a certain dimension, therefore, the feed volume of the hydrogen rich gas varies depending on the positional relation between the through hole and each of the cell units, so that the manifold should inevitably be made as a larger type so as to uniformly feed the hydrogen rich gas to each of the cell units. 
     In such circumstances, the invention has been achieved. It is an object of the invention to provide a fuel cell capable of uniformly feeding an anode fluid to each of the cell units even when the manifold is made as a small type. 
     SUMMARY OF THE INVENTION 
     So as to attain the object, in a first aspect of the invention, a fuel cell comprises a cell with an anode and a cathode connected together through an electrolyte membrane, a cell stack where a plurality of a cell unit with a separator equipped with an anode fluid path and the cell are laminated together, and a manifold for feeding an anode fluid to a position of the cell unit where the anode fluid path faces, characterized in that the manifold comprises a bottom plate equipped with a plurality of small openings facing the anode fluid path, a top plate where the flow space of the anode fluid is formed in the inside between the upper face of the bottom plate and the top place, and a fluid supply plate equipped with a flow conduit for feeding an anode fluid from the side part of the flow space along the face direction into the flow space; that a block group forming paths for dispersing the anode fluid fed from the flow conduit into the small openings is formed on the upper face of the bottom plate between the opening part of the flow conduit of the fluid supply plate into the flow space and the small openings; the flow rate of the anode fluid fed from the flow conduit of the fluid supply plate is reduced in the flow space, and the anode fluid at a reduced flow rate is allowed to influx the paths in the block group to be dispersed in the small openings. 
     Due to such characteristic feature, the anode fluid fed from the side face of the flow space along the face direction through the flow conduit of the fluid supply plate is fed into the flow space to reduce the flow rate of the anode fluid and the anode fluid at a reduced flow rate is allowed to influx the paths in the block group to be dispersed in the small openings. Therefore, the anode fluid can be dispersed in a plurality of the small openings in such a limited space of the manifold of a thin type, so that the anode fluid can uniformly be fed to each of the cell units, even when the manifold is made as a thin type. 
     In a second aspect of the invention, further, a fuel cell is characterized in that the paths formed with the block group are plurally formed and the width of such paths remote from the opening part of the flow conduit into the flow space is larger than the width of such paths close to the opening part of the flow conduit into the flow space. 
     Owing to such characteristic feature, the width of the paths remote from the opening part to which the anode fluid is fed is larger, so that the flow resistance in such remote paths is reduced for ready flowing. Thus, the anode fluid can be fed uniformly from a plurality of the paths into the small openings, despite the distances thereof from the opening part. 
     In a third aspect of the invention, further, a fuel cell is characterized in that the paths formed with the block group are plurally formed and the length of such paths remote from the opening part of the flow conduit into the flow space is shorter than the length of such paths close to the opening part of the flow conduit into the flow space. 
     Owing to such characteristic feature, the loss of the flow pressure in the remote paths is reduced for ready flowing because the length of the paths remote from the opening part of the flow conduit into the flow space where the anode fluid is fed is shorter, so that the anode fluid can uniformly be fed from a plurality of the paths into the small openings, despite the distances thereof from the opening part. 
     In a fourth aspect of the invention, a fuel cell is characterized in that a separator plate is arranged in such a manner that the separator plate separates the flow space through the block group on the opposite side of the small openings into a plurality of spaces along the direction of the small openings arranged and additionally divides the anode fluid into a plurality of the spaces. 
     Due to such characteristic feature, the anode fluid can be dispersed at a uniform state into a plurality of the small openings since the separator plate divides the anode fluid in a plurality of the spaces. 
     In a fifth aspect of the invention, a fuel cell is characterized in that a separator wall for separating the flow space through the block group on the opposite side of the small openings is arranged along the direction of the small openings arranged, where the opening part of the flow conduit into the flow space is formed in a manner corresponding to a plurality of the spaces separated with the separator wall. 
     Due to such characteristic feature, the anode fluid can be transferred from the opening parts corresponding to a plurality of the spaces into a plurality of the spaces, so that the anode fluid can be dispersed in a plurality of the small openings in a secure and uniform manner. 
     In a sixth aspect of the invention, further, a fuel cell is characterized in that a block group and a fluid supply plate are additionally arranged on the bottom plate through the small openings on the opposite side of the block group and the fluid supply plate, along the face direction thereof. 
     Due to such characteristic feature, the anode fluid flowing in the paths between the block groups on both the sides of the small openings can be fed, so that the flow pressure of the anode fluid into the small openings can be raised to feed the anode fluid into the small openings. 
     In a seventh aspect of the invention, additionally, the opening parts of the flow conduits facing each other into the flow space are arranged in an inversed direction to each other along the direction of the small openings arranged. 
     Due to such characteristic feature, additionally, the anode fluid can be fed from the opening parts arranged in an inversed direction to each other along the direction of the small openings arranged, so that the feed distribution of the anode fluid along the direction of the small openings arranged can be suppressed. 
     In an eighth aspect of the invention, additionally, a fuel cell is characterized in that the small openings are arranged in such a manner that the small openings close to the opening parts of the flow conduits into the flow space are more apart from the block group lying between the opening parts and the small openings than the small openings remote from the opening parts. 
     Due to such characteristic feature, the micro openings are arranged at a slanting state between the block groups, so the feed distribution of the anode fluid can further be suppressed. 
     In a ninth aspect of the invention, further, a fuel cell is characterized in that a plurality of small openings facing the anode fluid path are arranged on the top plate and the cell stacks are individually arranged on the bottom part of the bottom plate and the top part of the top plate. 
     Due to such characteristic feature, the cell stacks are arranged on both the sides of the manifold, while the manifold lies between the cell stacks. Therefore, the anode fluid can be fed from the manifold of a thin type to many cells. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view of the appearance of a fuel cell in a first embodiment. 
         FIG. 2  is a perspective view of the decomposed outer manifold. 
         FIG. 3  is a view of the appearance of the inner face of the bottom plate. 
         FIG. 4  is a view of the appearance of the inner face of the bottom plate, depicting the flow status of a fuel flowing on the bottom plate. 
         FIG. 5  is a view of the appearance of the inner face of the bottom plate of the outer manifold in a fuel cell in a second embodiment. 
         FIG. 6  is a view of the appearance of the inner face of the bottom plate of the outer manifold in a fuel cell in a third embodiment. 
         FIG. 7  is a view of the appearance of the inner face of the bottom plate of the outer manifold in a fuel cell in a fourth embodiment. 
         FIG. 8  is a view of the appearance of the inner face of the bottom plate of the outer manifold in a fuel cell in a fifth embodiment. 
         FIG. 9  is a view of the appearance of the inner face of the bottom plate of the outer manifold in a fuel cell in a sixth embodiment. 
         FIG. 10  is a perspective view of the decomposed outer manifold in a fuel cell in a seventh embodiment. 
         FIG. 11  is a view of the appearance of the fuel cell in the seventh embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     (First Embodiment) 
     A first embodiment is now described with reference to  FIGS. 1 through 4 . 
       FIG. 1  is a view of the appearance of a fuel cell in the first embodiment;  FIG. 2  is a perspective view of the decomposed outer manifold; and  FIG. 3  shows the appearance of the inner face of the bottom plate; and  FIG. 4  shows the status of a fuel flowing on the bottom plate. 
     As shown in the figures, a fuel cell  1  in this mode is equipped with an outer manifold  2  as a manifold for feeding a fuel (hydrogen) as an anode fluid, where hydrogen is fed from the outer manifold  2  to a cell stack  3 . The outer manifold  2  is connected with a fuel supply part not shown in the figures, for feeding hydrogen obtained from for example a hydrogen-absorbing alloy, while a control circuit not shown in the figures is connected with the electricity generation part of the cell stack  3 . 
     The cell  4  of the cell stack  3  is a membrane electrode assembly, where an anode-side catalyst (anode) and a cathode-side catalyst (cathode) are equipped on both the sides of a solid polymer electrolyte membrane as an electrolyte membrane. Then, a cell unit  11  is formed by alternately stacking a separator  5  with an anode fluid path (not shown in the figures) and a cathode fluid path  7  formed at a state of their sitting back to each other and the cell  4 . The cell stack  3  is constructed by stacking together a plurality of the cell unit  11 . So as to uniformly feed hydrogen in the cell stack  3  by uniformly dividing hydrogen in the anode fluid path of the separator  5  stacked in each cell unit  11  in the fuel cell  1  of such stack structure, an outer manifold  2  is equipped. 
     Herein, the separator  5  is not limited to the shape where the anode fluid path and the cathode fluid path  7  are formed at a state of their sitting back to back. The separator may be in any shape where the anode fluid can be fed to the anode and the cathode fluid can be fed to the cathode. 
     The outer manifold  2  is now described below with reference to  FIGS. 2 through 4 . 
     As shown in  FIG. 2 , the outer manifold  2  comprises a top plate  12  and a bottom plate  13 , where a hydrogen flow space  14  is formed between the inner face of the top plate  12  and the upper face of the bottom plate  13 . A fluid supply plate  15  is arranged on the side part of the bottom plate  13  along the face direction at a state such that the fluid supply plate and the bottom plate are on the same face, while a flow conduit  16  for feeding hydrogen into the flow space  14  from the side part of the flow space  14  along the face direction is formed on the fluid supply plate  15 . The top plate  12  is arranged over the bottom plate  13  and the fluid supply plate  15 , while the flow conduit  16  is arranged between the inner face of the top plate  12  and the upper face of the fluid supply plate  15 . 
     An opening part  17  with an opening on the side of the flow space  14  is arranged in the flow conduit  16 , and the opening part  17  is in communication with the influx part  18  on the bottom plate  13 . The end of the flow conduit  16  is a fuel supply port  19 . The fuel supply port  19  is connected with a fuel supply part not shown in the figure. 
     As shown in  FIGS. 2 and 3 , a plurality of small openings  24  (12 small openings in the depicted example) facing the anode fluid path of the cell unit  11  (see  FIG. 1 ) are arranged on the upper face of the bottom plate  13 . The small openings  24  are arranged in an array in such a manner that one or more such small openings  24  can be arranged in one cell unit  11  (see  FIG. 1 ). 
     In the depicted example, the small openings  24  are formed in an array of 12 small openings. A great number of small openings  24  may be formed for example by forming two or more such arrays, each array comprising 12 small openings. 
     A block group  25  is formed between the influx part  18  and the small openings  24  on the upper face of the bottom plate  13 , so that the block group  25  forms paths  26  for dispersing hydrogen fed from the influx part  18  into the small openings  24 . 
     As shown in  FIG. 4 , a plurality of blocks  27  is arranged in the block group  25 , while the spaces between the blocks  27  are the paths  26 . The blocks are arranged in such a manner that the width of blocks  27  close to the influx part  18  (the opening part  17  of the flow conduit  16 ) is larger than the width of blocks  27  remote from the influx part  18  (the opening part  17  of the flow conduit  16 ). In other words, the width H of the paths  26  remote from the influx part  18  (the opening part  17  of the flow conduit  16 ) is larger than the width h of the paths  26  close to the influx part  18  (the opening part  17  of the flow conduit  16 ), so that the pressure loss in the paths  26  remote from the influx part  18  (the opening part  17  of the flow conduit  16 ) is reduced. 
     A prevention wall preventing the efflux of hydrogen into the opposite side of the influx part  18  of hydrogen may be arranged through the small openings  24 , on the opposite side of the block group  25 , to securely retain the pressure for hydrogen supply into the small openings  24 . 
     Because the width H of the paths  26  remote from the influx part  18  (the opening part  17  of the flow conduit  16 ) is larger than the width h of the paths  26  close to the influx part  18  (the opening part  17  of the flow conduit  16 ), hydrogen flowing from the paths  26  into the small openings  24  can be divided at a uniform volume, despite the distances from the opening part  17  of the flow conduit  16 . Hydrogen uniformly divided in the small openings  24  flows downward (along the direction crossing with the flow direction in the paths  26 ) from the small openings  24  to be fed into the anode fluid path of each cell unit  11  (see  FIG. 1 ). 
     As shown in  FIG. 4 , hydrogen is fed from the fuel supply port  19  of the fluid supply plate  15  in the outer manifold  2 , which is then transferred from the flow conduit  16  through the opening part  17  and the influx part  18  to the flow space  14 , for dispersion along the plane direction. Hydrogen at a reduced flow rate due to the dispersion in the flow space  14  is divided in a plurality of the paths  26  in the block group  25  for flowing. 
     As described above (as shown in  FIG. 3 ) as to a plurality of the paths  26 , the width H of the paths  26  remote from the opening part  17  of the flow conduit  16  is larger than the width h of the paths  26  close to the opening part  17  of the flow conduit  16 , so that hydrogen transferred is uniformly divided in the paths  26  despite the distances from the opening part  17  of the flow conduit  16 . Hydrogen uniformly divided in the paths  26  flows downward (along the direction crossing with the flow direction in the paths  26 ) to be fed to the anode fluid path of the cell unit  11  (see  FIG. 1 ). 
     In the fuel cell  1  feeding hydrogen through the outer manifold  2  to the cell stack  3 , therefore, hydrogen fed from the side part along the face direction into the flow space  14  is dispersed in the flow space  14  and then divided uniformly in the paths  26  in the block group  25 , so that the hydrogen flowing in the paths  26  is at such a uniform volume that hydrogen is transferred into the small openings  24 . Accordingly, hydrogen can be fed uniformly to each cell unit in a manifold of a thin type, with no need for a manifold having a larger thickness, for example via the arrangement of a large dispersion space to make a large-type manifold. 
     Second Embodiment 
     With reference to  FIG. 5 , a second embodiment is described below. 
       FIG. 5  shows the appearance of the inner face of the bottom plate of the outer manifold in a fuel cell in the second embodiment. The members except for the bottom plate  13  are the same as those in the first embodiment. The same members as the members for the bottom plate  13  shown in  FIG. 3  (the first embodiment) are marked with the same symbols. Accordingly, overlapping descriptions are skipped. 
     As shown in the figure, a block group  32  is formed between the influx part  18  and the small openings  24  on the upper face of the bottom plate  13 . The block group  32  forms paths  33  for dispersing hydrogen fed from the communication hole  23  into the small openings  24 . A plurality of blocks  34  are arranged in the block group  32 , and the spaces between the blocks  34  are the path  33 . 
     The width (along the left and right direction in the figure) of the blocks  34  close to the influx part  18  (the opening part  17  of the flow conduit  16 ) is larger than the width of the blocks  34  remote from the influx part  18  (the opening part  17  of the flow conduit  16 ). In other words, the width H of the paths  33  remote from the influx part  18  (the opening part  17  of the flow conduit  16 ) is larger than the width h of the paths  33  close to the influx part  18  (the opening part  17  of the flow conduit  16 ), so that the pressure loss in the paths  33  remote from the influx part  18  (the opening part  17  of the flow conduit  16 ) is reduced. 
     Additionally, the length (along the upper and down direction in the figure) of the blocks  34  close to the influx part  18  (the opening part  17  of the flow conduit  16 ) is larger than the length of the blocks  34  remote from the influx part  18  (the opening part  17  of the flow conduit  16 ). In other words, the length l of the paths  33  remote from the influx part  18  (the opening part  17  of the flow conduit  16 ) is shorter than the length L of the paths  33  close to the influx part  18  (the opening part  17  of the flow conduit  16 ), so that the pressure loss in the paths  33  remote from the influx part  18  (the opening part  17  of the flow conduit  16 ) is reduced. 
     It is possible to modify only the length of the paths while equally retaining the width of a plurality of the blocks  34  in the block group  32  to make the width of the resulting paths equal. 
     By modifying the width and length of the paths  33 , further, hydrogen flowing from the paths  33  into the small openings  24  is divided at a uniform volume, despite the distance of the flow conduit  16  from the opening part  17 . Hydrogen uniformly divided in the small openings  24  flows downward (along the direction crossing with the direction of the influx the paths  33 ) from the small openings  24  to be fed into the anode fluid path of each cell unit  11  (see  FIG. 1 ). 
     Third Embodiment 
     With reference to  FIG. 6 , a third embodiment is described. 
       FIG. 6  shows the appearance of the inner face of the bottom plate of the outer manifold in a fuel cell in the third embodiment. The members except for the bottom plate  13  are the same as those in the first embodiment, and the same members as the members for the bottom plate  13  (the first embodiment) shown in  FIG. 3  are marked with the same symbols. Accordingly, overlapping descriptions are skipped. 
     A separator plate  36  separating the flow space  14  lying through the block group  25  on the opposite side of the small openings  24  into two spaces  14   a ,  14   b  along the direction of the arranged small openings  24  (along the left and right direction in the figure) is arranged, while the separator plate  36  is arranged at a state such that the separator plate  36  may separate the influx part  18  (the opening part  17  of the flow conduit  16 ) into two equal portions. In other words, the separator plate  36  can divide hydrogen fed from the opening part  17  of the flow conduit  16  into the two spaces  14   a ,  14   b . Therefore, hydrogen can be divided into the two spaces  14   a ,  14   b  with the separator plate  36 , so that hydrogen can be dispersed at a uniform state into a plurality of the small openings  24 . 
     Herein, the separator plate  36  may be arranged on the bottom plate  13  in the second embodiment as shown in  FIG. 5 . 
     Fourth Embodiment 
     With reference to  FIG. 7 , a fourth embodiment is now described. 
       FIG. 7  shows the appearance of the inner face of the bottom plate of the outer manifold in the fuel cell in the fourth embodiment. The members except for the bottom plate  13  are the same members as in the first embodiment. The same members as the members for the bottom plate  13  shown in  FIG. 3  (the first embodiment) are marked with the same symbols. Accordingly, overlapping descriptions are skipped. 
     A separator wall  51  separating the flow space  14  through the block group  25  on the opposite side of the small openings  24  into two spaces  14   a ,  14   b  along the direction of the small openings  24  is arranged, so that influx parts  55   a ,  55   b  are formed in a manner corresponding to the two spaces  14   a ,  14   b  on the bottom plate  13 . On the side part of the bottom plate  13  on the side of the influx parts  55   a ,  55   b  along the face direction, a fluid supply plate  52  is arranged at a state such that the fluid supply plate and the bottom plate  13  are on the same face, so that flow conduits  53   a ,  53   b  are formed on the fluid supply plate  52 , for feeding hydrogen from the side of the flow space  14  along the face direction into the flow space  14 . 
     An opening part  54   a  in communication with the influx part  55   a  of the flow space  14   a  is arranged in the flow conduit  53   a , while in the flow conduit  53   b , an opening part  54   b  in communication with the influx part  55   b  of the flow space  14   b  is arranged. The ends of the flow conduits  53   a ,  53   b  are fuel supply ports  56   a ,  56   b , and a fuel supply part not shown in the figure is connected with the fuel supply ports  56   a ,  56   b . A top plate not shown in the figure is arranged over the bottom plate  13  and the fluid supply plate  52 , and the flow conduits  53   a ,  53   b  are arranged between the inner face of the top plate and the upper face of the fluid supply plate  52 . 
     In the outer manifold described above, hydrogen fed into the flow conduits  53   a ,  53   b  is transferred through the opening parts  54   a ,  54   b  and the influx parts  55   a ,  55   b  into the individual spaces  14   a ,  14   b , which is then fed through the paths  26  in the block group  25  into the small openings  24 . Hence, hydrogen is transferred into the two spaces  14   a ,  14   b  due to the separation wall  51 , so that hydrogen can be dispersed securely at a uniform state in a plurality of the small openings  24 . 
     Fifth Embodiment 
     With reference to  FIG. 8 , a fifth embodiment is described below. 
       FIG. 8  shows the appearance of the inner face of the bottom plate of the outer manifold in a fuel cell in the fifth embodiment. The members except for the bottom plate  13  are the same as those in the first embodiment, and the same members as the members for the bottom plate  13  shown in  FIG. 3  (the first embodiment) are marked with the same symbols. Accordingly, overlapping descriptions are skipped. 
     In the fifth embodiment as shown in the figure, a block group  25  is additionally arranged through the small openings  24  on the opposite side (on the opposite side along the face direction) of the block group  25  on the bottom plate in the embodiment as shown in  FIG. 3 . In other words, a block group  25  is additionally arranged on the lower side of the small openings  24  in the figure and faces the block group  25  on the upper side in the figure. On the lower side of the bottom plate  13  in the figure, a fluid supply plate  15  is arranged for feeding hydrogen from the paths  26  in the block groups  25  on both the sides of the small openings  24 . 
     A conduit communication plate  61  is arranged on the side of the bottom plate  13 , and a communication path  62  is formed for allowing the fuel supply ports  19  of the two fluid supply plates  15  to be in communication. Then, a fuel supply path  63  is in communication with the communication path  62 . When hydrogen is fed from the fuel supply path  63 , hydrogen is transferred through the communication path  62  to the fuel supply ports  19  of the two fluid supply plates  15 , where hydrogen is dispersed from both the sides of the small openings  24  into the flow space  14 . Hydrogen is fed from the paths  26  between the two block groups  25  into the individual small openings  24 . 
     Therefore, the flow pressure of hydrogen into the small openings  24  between the two block groups  25  can be raised so that hydrogen can be fed stably into the small openings  24 . 
     Sixth Embodiment 
     With reference to  FIG. 9 , a sixth embodiment is now described below. 
       FIG. 9  depicts the appearance of the inner face of the bottom plate of the outer manifold in a fuel cell in the sixth embodiment. Since the members except for the bottom plate  13  are the same as those in the first embodiment, the same members as those for the bottom plate  13  shown in  FIG. 3  (the first embodiment) are marked with the same symbols. Accordingly, overlapping descriptions are skipped. 
     The sixth embodiment differs from the fifth embodiment as shown in  FIG. 8 , from the respects of the width of the paths in the block groups and the influx position of hydrogen on the fluid supply plate and additionally from the respect of the state of the arranged small openings. Therefore, the same members as the members in  FIG. 8  are marked with the same symbols. 
     On both the sides of the bottom plate  13  along the face direction, fluid supply plates  71 ,  81  are individually arranged at a state such that the fluid supply plates and the bottom plate  13  are on the same face, while flow conduits  72 ,  82  are formed on the fluid supply plates  71 ,  81 , for feeding hydrogen into the flow space  14  from both the sides of the flow space  14  (along the upper and down direction in the figure) along the face direction. 
     An opening part  74  with an opening on the side of the flow space  14  is arranged in the flow conduit  72 , while the opening part  74  is in communication with the influx part  75  on the bottom plate  13 . The end of the flow conduit  72  is a fuel supply port  73 . Similarly, an opening part  84  with an opening on the side of the flow space  14  is arranged in the flow conduit  81 , while the opening part  84  is in communication with the influx part  85  on the bottom plate  13 . The end of the flow conduit  81  is the fuel supply port  83 . 
     On the side part of the bottom plate  13  is arranged a conduit communication plate  61 , and a communication path  62  allowing the fuel supply ports  73 ,  83  of two fluid supply plates  71 ,  81  to be in communication is formed on the conduit communication plate  61 . A fuel supply path  63  is in communication with the communication path  62 . When hydrogen is fed from the fuel supply path  63 , specifically, hydrogen is transferred through the communication path  62  to the fuel supply ports  73 ,  83  of the two fluid supply plates  71 ,  81 . 
     On the upper face of the bottom plate  13 , a plurality of small openings  24  (12 small openings in the depicted example) facing the anode fluid path of the cell unit  11  (see  FIG. 1 ) are formed. So as to arrange one or plural small openings  24  in one cell unit  11  (see  FIG. 1 ), for example, the small openings  24  are arranged in an array. On the upper face of the bottom plate  13  between the influx part  75  and the small openings  24  and between the influx part  85  and the small openings  24 , individual block groups  38  are formed. Paths  40  for dispersing hydrogen fed from the influx parts  75 ,  85  into the small openings  24  are formed with the block groups  38 . A plurality of blocks  39  are arranged in the block groups  38 , and the paths  40  are formed between the blocks  39 . The width of the blocks  39  is structurally uniform, so that the width of the paths  40  is uniform. 
     The opening parts  74 ,  84  of the flow conduits  72 ,  82  through the fluid supply plates  71 ,  81  facing each other into the flow space  14  are arranged in an inversed direction to each other along the direction of the small openings  24  arranged (along the left and right direction in the figure). In other words, the opening part  74  of the flow conduit  72  is arranged in the vicinity of the end on the left side in the figure, while the opening part  84  of the flow conduit  82  is arranged in the vicinity of the end on the right side in the figure. 
     Additionally, the small openings  24  are arranged in such a manner that the micro openings  24  close to the opening parts  74 ,  84  of the flow conduits  72 ,  82  are more apart from the block groups  38  lying between the opening parts  74 ,  84  than the small openings  24  remote from the opening parts  74 ,  84 . In other words, the small openings  24  are arranged at a slanting state toward the upper right in the figure. 
     Therefore, hydrogen is fed from the opening parts  74 ,  84  arranged in an inversed direction to each other along the direction of the small openings  24  arranged, so that hydrogen is fed into the small openings  24  arranged at a state slanting toward the direction apart from the opening parts  74 ,  84 , so that the hydrogen feed distribution along the direction of the arranged small openings  24  is more highly suppressed, leading to more uniform feeding of hydrogen into the small openings  24 . 
     Seventh Embodiment 
     With reference to  FIGS. 10 and 11 , a seventh embodiment is now described. 
       FIG. 10  is a perspective view of the disassembled outer manifold of a fuel cell in the seventh embodiment; and  FIG. 11  depicts the appearance of a fuel cell in the seventh embodiment. Herein, the same members as those in the first embodiment ( FIGS. 1 and 2 ) are marked with the same symbols. Therefore, overlapping descriptions are skipped. 
     In the embodiment as shown in the figure, an outer manifold  20  comprises small openings  22  formed through a top plate  28 . The other structure is the same as that of the outer manifold shown in  FIG. 2 . The small openings  22  are formed in a manner corresponding to the small openings  24  arranged through the bottom plate  13 . As shown in  FIG. 11 , additionally, individual cell stacks  3  are arranged on the lower side of the bottom plate  13  and the upper side of the top plate  28 . 
     By applying the outer manifold  20  with the small openings  22  formed through the top plate  28 , the cell stacks  3  can be arranged through the outer manifold  20  on both the sides of the outer manifold  20 . An anode fluid can be fed into two cells  4  with the outer manifold  20  of a thin type. 
     In the embodiment, hydrogen is exemplified as an anode fluid. However, the embodiment may be applicable to the supply of other fuels including methanol. 
     Since an anode fluid can be dispersed into a plurality of small openings in the limited space of the manifold of a thin type, the anode fluid can be fed uniformly to each cell even when the manifold is made as such thin type.