JP5283520B2 - Fuel cell stack - Google Patents

Description

  The present invention includes a power generation unit including two electrolytes / electrode structures in which electrodes are disposed on both sides of each electrolyte, and three separators stacked alternately with the electrolyte / electrode structures, In the unit, there are formed first to fourth reaction gas flow paths for flowing a predetermined reaction gas along the power generation surface, and a reaction gas inlet communication hole and a reaction gas outlet communication hole for flowing the reaction gas in the stacking direction. In addition, the present invention relates to a fuel cell stack in which a cooling medium flow path for flowing a cooling medium is formed between the power generation units.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are disposed on both sides of an electrolyte membrane made of a polymer ion exchange membrane is provided by a pair of separators. The unit cell is sandwiched. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of unit cells.

  In the above fuel cell, a fuel gas channel (reactive gas channel) for flowing a fuel gas opposite to the anode side electrode and an oxidant gas for flowing the cathode gas facing the cathode side electrode in the plane of the separator. The oxidant gas flow path (reaction gas flow path) is provided. Further, between the separators, a cooling medium flow path for flowing the cooling medium is provided along the surface direction of the separator.

  By the way, the fuel cell stack may adopt a so-called thinning cooling structure in which a cooling medium flow path is formed between a predetermined number of unit cells. In a fuel cell having this kind of thinning cooling structure, for example, as disclosed in Patent Document 1 shown in FIG. 14, a separator 1, a cell 2, a separator 3, a cell 2 and a separator 4 are laminated.

  In the cell 2, the fuel electrode 2b and the air electrode 2c are disposed on both surfaces of the solid polymer electrolyte membrane 2a. A fuel gas passage 5 a is formed between the separator 1 and one cell 2, and an oxidant gas passage 6 a is formed between the separator 3 and the one cell 2. A fuel gas passage 5 b is formed between the separator 3 and the other cell 2, and an oxidant gas passage 6 b is formed between the separator 4 and the other cell 2. A cooling water passage 7 is formed between the separators 1 and 4 adjacent to each other.

JP 2002-289223 A

  In the fuel cell, the cooling water passage 7 is provided adjacent to the fuel gas passage 5a, and the cooling water passage 7 is provided adjacent to the oxidant gas passage 6b. On the other hand, the fuel gas passage 5 b and the oxidant gas passage 6 a are provided adjacent to each other and are separated from the cooling water passage 7.

  For this reason, the fuel gas passage 5a has a lower temperature than the fuel gas passage 5b, and the oxidant gas passage 6b has a lower temperature than the oxidant gas passage 6a. Accordingly, water generated during power generation by the fuel cell is likely to condense in the fuel gas passage 5a and the oxidant gas passage 6b having a low temperature. Thereby, in the fuel gas passage 5a and the oxidant gas passage 6b, there is a problem that the flow of the fuel gas and the oxidant gas is hindered by the generated water, and stable power generation is not performed.

  The present invention is a fuel cell having a thin-out cooling structure of this type, which has a simple and economical configuration, and can efficiently discharge generated water in the reaction gas flow path and reliably perform efficient power generation. An object is to provide a battery stack.

  The present invention includes a power generation unit including two electrolytes / electrode structures in which electrodes are disposed on both sides of each electrolyte, and three separators stacked alternately with the electrolyte / electrode structures, In the unit, there are formed first to fourth reaction gas flow paths for flowing a predetermined reaction gas along the power generation surface, and a reaction gas inlet communication hole and a reaction gas outlet communication hole for flowing the reaction gas in the stacking direction. In addition, the present invention relates to a fuel cell stack in which a cooling medium flow path for flowing a cooling medium is formed between the power generation units.

  The fuel cell stack includes an inlet-side communication passage portion that communicates the first to fourth reaction gas flow paths and the reaction gas inlet communication holes, the first to fourth reaction gas flow paths and the reaction gas outlet communication holes, The first and third reaction gas flow paths, and the second and fourth reaction gas flow paths respectively flow the same reaction gas.

  In addition, at least the first reaction gas flow channel adjacent to the cooling medium flow channel is set such that the flow channel cross-sectional area of the outlet-side communication channel portion is set larger than the flow channel cross-sectional area of the inlet-side communication channel portion. The third reactive gas flow channel that is separated from the cooling medium flow channel with respect to the reactive gas flow channel is configured such that the flow channel cross-sectional area of the outlet-side communication channel portion is set smaller than the flow channel cross-sectional area of the inlet-side communication channel portion. Yes.

  In addition, the inlet-side communication passage portion and the outlet-side communication passage portion have a hole portion that penetrates the separator, and the first reaction gas flow path is configured such that the hole portion of the outlet-side communication passage portion is the inlet-side communication passage. The third reaction gas flow path is configured such that the hole portion of the outlet-side communication passage portion is smaller than the hole portion of the inlet-side communication passage portion. The shape is preferably set.

  Further, the inlet-side communication passage portion and the outlet-side communication passage portion have a connection path provided in the separator, and the first reaction gas flow path is configured such that the connection path of the outlet-side communication path portion is the inlet-side communication path. The third reaction gas flow path is configured such that the connection path of the outlet-side communication path section is connected to the inlet-side communication path section. It is preferable that the dimension is set to be smaller in at least the width direction or the depth direction than the connection path.

  Furthermore, the inlet-side communication path portion and the outlet-side communication path portion have a connection path provided in the separator, and the first reaction gas flow path has the connection path of the outlet-side communication path section connected to the inlet-side communication path. The third reaction gas flow path is set to have a larger cross-sectional area or shorter than the connection path of the passage part, and the connection path of the outlet side communication path part is more than the connection path of the inlet side communication path part. Is preferably set to have a small cross-sectional area or a long length.

  According to the present invention, the first reaction gas flow channel on the low temperature side adjacent to the cooling medium flow channel is set such that the flow passage cross-sectional area of the outlet side communication passage portion is larger than the flow passage cross-sectional area of the inlet side communication passage portion. ing. For this reason, the pressure loss of the outlet side communication passage portion is reduced, and the generated water condensed in the first reaction gas channel on the low temperature side can be discharged well and reliably.

  On the other hand, the third reaction gas flow channel on the high temperature side that is separated from the cooling medium flow channel is set such that the flow channel cross-sectional area of the outlet-side communication channel portion is smaller than the flow channel cross-sectional area of the inlet-side communication channel portion. Therefore, the pressure loss of the inlet side communication passage portion is reduced, the pressure loss is maintained constant in the third reaction gas flow channel and the first reaction gas flow channel, and the gas distribution property is improved.

  In addition, the pressure of the third reaction gas channel is higher than the pressure of the first reaction gas channel, and the temperature of the third reaction gas channel is higher than the temperature of the first reaction gas channel. . That is, in the third reaction gas flow path, the temperature becomes higher and it becomes easier to dry than the first reaction gas flow path, while the pressure becomes higher and the humidity becomes higher than the first reaction gas flow path. As a result, the third reactive gas flow channel and the first reactive gas flow channel can suppress a difference in humidity environment, improve the power generation efficiency of the power generation unit satisfactorily, and reliably perform stable power generation. Become.

It is a principal part disassembled perspective explanatory drawing of the electric power generation unit which comprises the fuel cell stack which concerns on the 1st Embodiment of this invention. FIG. 2 is a sectional view of the fuel cell stack taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional explanatory view of the fuel cell stack. It is front explanatory drawing of the 1st separator which comprises the said electric power generation unit. It is front explanatory drawing of the 2nd separator which comprises the said electric power generation unit. It is explanatory drawing of the internal temperature of a 1st fuel gas flow path and a 2nd fuel gas flow path. It is explanatory drawing of the internal pressure of the said 1st fuel gas flow path and the said 2nd fuel gas flow path. It is explanatory drawing of the internal humidity of the said 1st fuel gas flow path and the said 2nd fuel gas flow path. FIG. 6 is an explanatory diagram of the relationship between the pressure and flow rate of the first fuel gas channel and the second fuel gas channel in an unpowered state. FIG. 5 is an explanatory diagram of a relationship between a pressure and a flow rate of the first fuel gas channel and the second fuel gas channel in a power generation state. It is a principal part disassembled perspective explanatory drawing of the electric power generation unit which comprises the fuel cell stack concerning the 2nd Embodiment of this invention. It is front explanatory drawing of the 1st separator which comprises the said electric power generation unit. It is front explanatory drawing of the 2nd separator which comprises the said electric power generation unit. It is explanatory drawing of the fuel cell which has the conventional thinning cooling structure.

  FIG. 1 is an exploded perspective view of a main part of a power generation unit 12 constituting a fuel cell stack 10 according to a first embodiment of the present invention.

  As shown in FIGS. 2 and 3, the fuel cell stack 10 is configured by stacking a plurality of power generation units 12 along the horizontal direction (arrow A direction). The power generation unit 12 includes a first separator 14, a first electrolyte membrane / electrode structure (electrolyte / electrode structure) (MEA) 16 a, a second separator 18, a second electrolyte membrane / electrode structure 16 b, and a third separator 20. Provide.

  The 1st separator 14, the 2nd separator 18, and the 3rd separator 20 are comprised, for example with the steel plate, the stainless steel plate, the aluminum plate, the plating treatment steel plate, or the metal plate which gave the surface treatment for anticorrosion to the metal surface. The 1st separator 14, the 2nd separator 18, and the 3rd separator 20 have cross-sectional uneven | corrugated shape by pressing a metal thin plate into a waveform. In addition, you may comprise the 1st separator 14, the 2nd separator 18, and the 3rd separator 20 with a carbon separator, for example.

  As shown in FIGS. 1 and 2, the first electrolyte membrane / electrode structure 16a is set to have a smaller surface area than the second electrolyte membrane / electrode structure 16b. The first and second electrolyte membrane / electrode structures 16a and 16b include, for example, a solid polymer electrolyte membrane 22 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side sandwiching the solid polymer electrolyte membrane 22 The electrode 24 and the cathode side electrode 26 are provided. The anode side electrode 24 constitutes a so-called stepped MEA having a smaller surface area than the cathode side electrode 26.

  The anode side electrode 24 and the cathode side electrode 26 are uniformly coated on the surface of the gas diffusion layer with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 22.

  As shown in FIG. 1, the upper end edge (in the direction of arrow C) in the long side direction of the power generation unit 12 communicates with each other in the direction of arrow A to oxidize for supplying an oxidant gas, for example, an oxygen-containing gas. An agent gas inlet communication hole (reaction gas inlet communication hole) 30a and a fuel gas inlet communication hole (reaction gas inlet communication hole) 32a for supplying a fuel gas, for example, a hydrogen-containing gas, are provided.

  A fuel gas outlet communication hole (reactive gas outlet communication hole) 32b that communicates with each other in the direction of arrow A and discharges fuel gas at the lower end edge in the long side direction (arrow C direction) of the power generation unit 12, and An oxidant gas outlet communication hole (reaction gas outlet communication hole) 30b for discharging the oxidant gas is provided.

  At one edge of the power generation unit 12 in the short side direction (arrow B direction), there is provided a cooling medium inlet communication hole 34a that communicates with each other in the direction of arrow A and supplies a cooling medium. A cooling medium outlet communication hole 34b for discharging the cooling medium is provided at the other end edge in the short side direction.

  On the surface 14a of the first separator 14 facing the first electrolyte membrane / electrode structure 16a, for example, a first fuel gas flow path (first reactive gas flow path) 36 having a plurality of grooves extending in the direction of arrow C. Is provided. The first fuel gas flow path 36 communicates with the fuel gas inlet communication hole 32a and the fuel gas outlet communication hole 32b via the first inlet side communication path portion 38a and the first outlet side communication path portion 38b.

  As shown in FIGS. 1 and 4, the first inlet side communication passage portion 38a is provided on the surface 14b opposite to the surface 14a and includes a plurality of connection passages 40a communicating with the fuel gas inlet communication hole 32a. A plurality of through holes 42 a that penetrate the separator 14 in the stacking direction and communicate with the connecting passage 40 a and the first fuel gas passage 36 are provided. Similarly, the first outlet side communication passage portion 38b is provided on the surface 14b and communicates with the fuel gas outlet communication hole 32b, and the first separator 14 passes through the first separator 14 in the stacking direction. And a plurality of through holes 42 b communicating with the first fuel gas channel 36.

  The flow passage cross-sectional area of the first outlet side communication passage portion 38b is set larger than the flow passage cross-sectional area of the first inlet side communication passage portion 38a. In the first embodiment, the opening diameter D1 of the through hole 42b of the first outlet side communication path portion 38b is set larger than the opening diameter D2 of the through hole 42a of the first inlet side communication path portion 38a. The connection path 40b of the first outlet side communication path portion 38b is set to a dimension larger in the width direction than the connection path 40a of the first inlet side communication path portion 38a. The width dimensions of the connecting paths 40a and 40b are set corresponding to the opening diameters D1 and D2 of the through holes 42a and 42b, respectively.

  A part of the cooling medium flow path 44 that connects the cooling medium inlet communication hole 34 a and the cooling medium outlet communication hole 34 b is formed on the surface 14 b of the first separator 14.

  As shown in FIG. 1, the surface 18a of the second separator 18 facing the first electrolyte membrane / electrode structure 16a is connected to the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b. An agent gas channel (second reaction gas channel) 46 is formed. The first oxidizing gas channel 46 has a plurality of grooves extending in the direction of arrow C.

  On the surface 18b of the second separator 18 facing the second electrolyte membrane / electrode structure 16b, for example, a second fuel gas channel (third reaction gas channel) 48 having a plurality of grooves extending in the direction of arrow C. Is provided. The second fuel gas flow path 48 communicates with the fuel gas inlet communication hole 32a and the fuel gas outlet communication hole 32b via the second inlet side communication path portion 50a and the second outlet side communication path portion 50b.

  As shown in FIGS. 1 and 5, the second inlet side communication passage portion 50a includes a plurality of connection paths 52a provided on the surface 18a and communicating with the fuel gas inlet communication holes 32a, and the second separator 18 in the stacking direction. And a plurality of through holes 54 a that penetrate and communicate with the connecting passage 52 a and the second fuel gas passage 48. Similarly, the second outlet side communication path portion 50b is provided on the surface 18a and communicates with the fuel gas outlet communication hole 32b, and the second separator 18 passes through the second separator 18 in the stacking direction. And a plurality of through holes 54 b communicating with the second fuel gas channel 48.

  The second fuel gas flow channel 48 on the high temperature side that is separated from the cooling medium flow channel 44 with respect to the first fuel gas flow channel 36 has a flow passage cross-sectional area of the second outlet side communication passage portion 50b that is the second inlet side communication passage. It is set smaller than the channel cross-sectional area of the part 50a.

  Specifically, the opening diameter D4 of the through hole 54b of the second outlet side communication passage portion 50b is set to be smaller than the opening diameter D3 of the through hole 54a of the second inlet side communication passage portion 50a. The connection path 52b of the second outlet side communication path portion 50b is set to a dimension smaller in the width direction than the connection path 52a of the second inlet side communication path portion 50a.

  As shown in FIG. 1, the second oxidation that connects the oxidant gas inlet communication hole 30 a and the oxidant gas outlet communication hole 30 b to the surface 20 a of the third separator 20 facing the second electrolyte membrane / electrode structure 16 b. An agent gas flow path (fourth reaction gas flow path) 56 is formed. The second oxidizing gas channel 56 has a plurality of grooves extending in the direction of arrow C. A part of the cooling medium flow path 44 is formed on the surface 20 b of the third separator 20.

  As shown in FIGS. 1, 2, and 4, the first seal member 60 is integrally formed on the surfaces 14 a and 14 b of the first separator 14 around the outer peripheral edge of the first separator 14. As shown in FIGS. 1, 2, and 5, a second seal member 62 is integrally formed on the surfaces 18 a and 18 b of the second separator 18 around the outer peripheral edge of the second separator 18. The third seal member 64 is integrally formed on the surfaces 20a and 20b of the third separator 20 around the outer peripheral edge of the third separator 20 (see FIGS. 1 and 2).

  When the power generation units 12 are stacked on each other, the first power generation unit 12 and the third separator 20 included in the other power generation unit 12 extend in the direction of the arrow B. A cooling medium flow path 44 is formed (see FIGS. 1 and 3).

  The operation of the fuel cell stack 10 configured as described above will be described below.

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 30a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 32a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 34a.

  Therefore, the oxidant gas is introduced from the oxidant gas inlet communication hole 30 a into the first oxidant gas flow path 46 of the second separator 18 and the second oxidant gas flow path 56 of the third separator 20. The oxidant gas moves in the direction of arrow C (the direction of gravity) along the first oxidant gas flow path 46 and is supplied to the cathode side electrode 26 of the first electrolyte membrane / electrode structure 16a. It moves in the direction of arrow C along the oxidant gas flow path 56 and is supplied to the cathode electrode 26 of the second electrolyte membrane / electrode structure 16b.

  On the other hand, as shown in FIGS. 2 and 4, the fuel gas is supplied from the fuel gas inlet communication hole 32a to the connecting passage 40a that constitutes the first inlet side communication passage portion 38a of the first separator 14, and passes through the through hole 42a. It moves to the surface 14a side. For this reason, the fuel gas moves in the direction of gravity (arrow C direction) along the first fuel gas flow path 36 communicating with the through hole 42a, and is supplied to the anode side electrode 24 of the first electrolyte membrane / electrode structure 16a. Is done.

  Further, as shown in FIGS. 2 and 5, the fuel gas is supplied from the fuel gas inlet communication hole 32a to the connecting passage 52a constituting the second inlet side communication passage portion 50a of the second separator 18, and through the through hole 54a. It moves to the surface 18b side. Therefore, the fuel gas moves in the gravity direction (arrow C direction) along the second fuel gas flow path 48 communicating with the through hole 54a, and is supplied to the anode side electrode 24 of the second electrolyte membrane / electrode structure 16b. The

  Thus, in the first and second electrolyte membrane / electrode structures 16a and 16b, the oxidant gas supplied to the cathode side electrode 26 and the fuel gas supplied to the anode side electrode 24 are within the electrode catalyst layer. It is consumed by electrochemical reaction to generate electricity.

  Next, the oxidant gas consumed by being supplied to the cathode-side electrodes 26 of the first and second electrolyte membrane / electrode structures 16a and 16b is discharged in the direction of arrow A along the oxidant gas outlet communication hole 30b. The

  As shown in FIG. 4, the fuel gas supplied to and consumed by the anode-side electrode 24 of the first electrolyte membrane / electrode structure 16a passes through the through-hole 42b constituting the first outlet-side communication passage portion 38b. 1 separator 14 is led to the surface 14b side. The fuel gas led out to the surface 14b side is discharged to the fuel gas outlet communication hole 32b through the connection path 40b.

  Further, as shown in FIG. 5, the fuel gas consumed by being supplied to the anode side electrode 24 of the second electrolyte membrane / electrode structure 16b passes through the through hole 54b constituting the second outlet side communication passage portion 50b. The second separator 18 is led out to the surface 18a side. The fuel gas led out to the surface 18a side is discharged to the fuel gas outlet communication hole 32b through the connection path 52b.

  On the other hand, the cooling medium supplied to the cooling medium inlet communication hole 34 a is the cooling formed between the first separator 14 constituting one power generation unit 12 and the third separator 20 constituting the other power generation unit 12. After being introduced into the medium flow path 44, it flows in the direction of arrow B. The cooling medium cools the first and second electrolyte membrane / electrode structures 16a and 16b, and then is discharged into the cooling medium outlet communication hole 34b.

  In this case, in the first embodiment, as shown in FIG. 3, the first fuel gas passage 36 is adjacent to the cooling medium passage 44, while the second fuel gas passage 48 is the first oxidant gas. Adjacent to the flow path 46 and spaced from the cooling medium flow path 44. Thereby, the 1st fuel gas channel 36 tends to become low temperature rather than the 2nd fuel gas channel 48, and the drainage nature of generated water falls.

  Therefore, as shown in FIG. 4, the through hole 42 b of the first outlet side communication path portion 38 b is set to have a larger opening shape than the through hole 42 a of the first inlet side communication path portion 38 a, and the first outlet side The connection path 40b of the side communication path portion 38b is set to have a larger dimension in the width direction than the connection path 40a of the first inlet side communication path portion 38a. For this reason, the pressure loss of the first outlet side communication passage portion 38b is set to be smaller than the pressure loss of the first inlet side communication passage portion 38a, and the generated water condensed in the first fuel gas passage 36 on the low temperature side is excellent and It can be discharged reliably.

  On the other hand, as shown in FIG. 5, the second fuel gas flow channel 48 that is separated from the cooling medium flow channel 44 has a flow passage cross-sectional area of the second outlet side communication passage portion 50b that flows from the second inlet side communication passage portion 50a. It is set smaller than the road cross-sectional area. Specifically, the through hole 54b of the second outlet side communication passage portion 50b is set to have a smaller opening shape than the through hole 54a of the second inlet side communication passage portion 50a, and the second outlet side communication passage portion. The connection path 52b of 50b is set to have a smaller dimension in the width direction than the connection path 52a of the second inlet side communication path portion 50a.

  Accordingly, in the second fuel gas flow channel 48, the pressure loss of the second inlet side communication passage portion 50a is reduced, and the pressure loss of the second fuel gas flow channel 48 and the first fuel gas flow channel 36 is kept constant, It can prevent that the distribution property of fuel gas falls.

  Furthermore, as shown in FIG. 6, the temperature of the second fuel gas channel 48 that is separated from the cooling medium channel 44 is higher than that of the first fuel gas channel 36 adjacent to the cooling medium channel 44, The second fuel gas channel 48 is relatively easy to dry.

  On the other hand, as shown in FIG. 7, the first fuel gas channel 36 has a large pressure loss on the inlet side, and the second fuel gas channel 48 has a large pressure loss on the outlet side. For this reason, the second fuel gas flow channel 48 has a higher pressure than the first fuel gas flow channel 36, and the humidity tends to increase.

  As a result, as shown in FIG. 8, the temperature difference between the first fuel gas passage 36 and the second fuel gas passage 48 is balanced between the temperature and the pressure, thereby suppressing the difference between the humidity environments. Therefore, the power generation efficiency of the power generation unit 12 can be improved satisfactorily and stable power generation can be reliably performed.

  In particular, in the first embodiment, the humidity of the first fuel gas channel 36 and the second fuel gas channel 48 during power generation of each power generation unit 12 is maintained to be equal. Therefore, as shown in FIG. 9, the flow rate of the first fuel gas flow channel 36 adjacent to the cooling medium flow channel 44 is larger than the flow rate of the second fuel gas flow channel 48 in a state where power generation is not performed. In a state where the power generation unit 12 generates power, as shown in FIG. 10, uniform fuel gas distribution is achieved between the first fuel gas passage 36 on the low temperature side and the second fuel gas passage 48 on the high temperature side. It is done.

  In the first embodiment, in the first fuel gas flow path 36, the through hole 42b of the first outlet side communication path portion 38b has a larger opening shape than the through hole 42a of the first inlet side communication path portion 38a. In addition, the connecting passage 40b of the first outlet side communication passage portion 38b is set to have a larger dimension in the width direction than the connection passage 40a of the first inlet side communication passage portion 38a. Is not to be done. For example, by setting the number of through-holes 42b to be larger than the number of through-holes 42a, the flow passage cross-sectional area of the first outlet side communication passage portion 38b is larger than the flow passage cross-sectional area of the first inlet side communication passage portion 38a. Can also be set larger. The same applies to the second fuel gas channel 48.

  FIG. 11 is an exploded perspective view of a main part of the power generation unit 72 constituting the fuel cell stack 70 according to the second embodiment of the present invention. The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The power generation unit 72 includes a first separator 74, a first electrolyte membrane / electrode structure (electrolyte / electrode structure) 76a, a second separator 78, a second electrolyte membrane / electrode structure 76b, and a third separator 80.

  As shown in FIGS. 11 and 12, a first fuel gas passage 36 is provided on the surface 14a side of the first separator 74, and the first fuel gas passage 36, the fuel gas inlet communication hole 32a, and the fuel are provided. The gas outlet communication hole 32b communicates with the first inlet side communication passage portion 82a and the first outlet side communication passage portion 82b. The first inlet side communication path portion 82a has a plurality of connection paths 84a provided on the surface 14a, and the first outlet side communication path portion 82b has a plurality of connection paths 84b provided on the surface 14a. The connection paths 84 a and 84 b are formed between the protrusions that are integrally formed with the first seal member 60.

  The width dimension h1 of the connection path 84b of the first outlet side communication path portion 82b is set wider than the width dimension h2 of the connection path 84a of the first inlet side communication path section 82a. That is, the flow passage cross-sectional area of the first outlet side communication passage portion 82b is set larger than the flow passage cross-sectional area of the first inlet side communication passage portion 82a.

  As shown in FIGS. 11 and 13, a second fuel gas passage 48 is provided on the surface 18b side of the second separator 78, and the second fuel gas passage 48, the fuel gas inlet communication hole 32a, and the fuel are provided. The gas outlet communication hole 32b communicates with the second inlet side communication path portion 86a and the second outlet side communication path portion 86b. The second inlet side communication path portion 86a has a plurality of connection paths 88a provided on the surface 18b, while the second outlet side communication path portion 86b has a plurality of connection paths 88b provided on the surface 18b. The connection paths 88 a and 88 b are formed between the protrusions that are integrally formed with the second seal member 62.

  The width dimension h2 of the connection path 88b of the second outlet side communication path portion 86b is set to be narrower than the width dimension h1 of the connection path 88a of the second inlet side communication path section 86a. That is, the flow passage cross-sectional area of the second outlet side communication passage portion 86b is set smaller than the flow passage cross-sectional area of the second inlet side communication passage portion 86a.

  In the second embodiment configured as described above, the low temperature side first fuel gas flow channel 36 adjacent to the cooling medium flow channel 44 has a flow passage cross-sectional area of the first outlet side communication passage portion 82b as the first inlet. It is set larger than the flow path cross-sectional area of the side communication passage 82a. For this reason, the pressure loss of the 1st exit side communication channel part 82b becomes small, and the generated water condensed in the 1st fuel gas flow path 36 by the side of low temperature can be discharged | emitted favorably and reliably.

  On the other hand, the second fuel gas flow channel 48 on the high temperature side that is separated from the cooling medium flow channel 44 has a flow passage cross-sectional area of the second outlet side communication passage portion 86b that is larger than that of the second inlet side communication passage portion 86a. Is also set small (see FIG. 13). Therefore, the first fuel gas flow path 36 and the second fuel gas flow path 48 have the same effects as those of the first embodiment, such as maintaining a constant pressure loss and improving gas distribution.

  In the second embodiment, the width dimension of the connection path 84b of the first outlet side communication path portion 82b is set larger than the width dimension of the connection path 84a of the first inlet side communication path section 82a. It is not limited to. For example, the connection path 84b of the first outlet side communication path portion 82b may be set to a larger dimension in the depth direction than the connection path 84a of the first inlet side communication path section 82a, or has a large cross-sectional area and a short length. May be set. Similarly, the connection path 88b of the second outlet side communication path portion 86b may be set to a smaller dimension in the depth direction than the connection path 88a of the second inlet side communication path portion 86a, or a small cross-sectional area or It may be set to be long.

DESCRIPTION OF SYMBOLS 10, 70 ... Fuel cell stack 12, 72 ... Electric power generation unit 14, 18, 20, 74, 78, 80 ... Separator 16a, 16b, 76a, 76b ... Electrolyte membrane and electrode structure 22 ... Solid polymer electrolyte membrane 24 ... Anode Side electrode 26 ... Cathode side electrode 30a ... Oxidant gas inlet communication hole 30b ... Oxidant gas outlet communication hole 32a ... Fuel gas inlet communication hole 32b ... Fuel gas outlet communication hole 34a ... Cooling medium inlet communication hole 34b ... Cooling medium outlet communication Holes 36, 48 ... Fuel gas flow paths 38a, 38b, 50a, 50b, 82a, 82b, 86a, 86b ... Communication passage portions 40a, 40b, 52a, 52b, 84a, 84b, 88a, 88b ... Connection paths 42a, 42b, 54a, 54b ... through hole 44 ... cooling medium flow path 46, 56 ... oxidant gas flow path

Claims (4)

A power generation unit having two electrolyte / electrode structures in which electrodes are arranged on both sides of each electrolyte, and three separators stacked alternately with the electrolyte / electrode structures; The first to fourth reaction gas flow paths for flowing a predetermined reaction gas along the power generation surface, and the reaction gas inlet communication hole and the reaction gas outlet communication hole for flowing the reaction gas in the stacking direction are formed, A fuel cell stack in which a cooling medium flow path for flowing a cooling medium is formed between the power generation units,
An inlet-side communication passage portion that communicates the first to fourth reaction gas flow paths and the reaction gas inlet communication holes;
An outlet-side communication passage portion that communicates the first to fourth reaction gas flow paths and the reaction gas outlet communication holes;
With
The first and third reaction gas passages and the second and fourth reaction gas passages flow the same reaction gas, respectively.
At least the first reaction gas flow channel adjacent to the cooling medium flow channel is set such that the flow channel cross-sectional area of the outlet-side communication channel portion is larger than the flow channel cross-sectional area of the inlet-side communication channel portion,
The third reactive gas flow channel that is separated from the cooling medium flow channel with respect to the first reactive gas flow channel has a flow channel cross-sectional area of the outlet side communication channel portion that is greater than a flow channel cross sectional area of the inlet side communication channel portion. The fuel cell stack is characterized by being set to a small size. 2. The fuel cell stack according to claim 1, wherein the inlet-side communication path portion and the outlet-side communication path portion have a hole portion that penetrates the separator,
In the first reactive gas flow path, the hole portion of the outlet side communication passage portion is set to have a larger opening shape than the hole portion of the inlet side communication passage portion,
The fuel cell stack, wherein the third reactive gas flow path is configured such that the hole portion of the outlet side communication passage portion is smaller than the hole portion of the inlet side communication passage portion. The fuel cell stack according to claim 1 or 2, wherein the inlet-side communication path portion and the outlet-side communication path portion have a connection path provided in the separator,
The first reaction gas flow path is configured such that the connection path of the outlet side communication path portion is set to a size that is at least larger in the width direction or the depth direction than the connection path of the inlet side communication path section.
The third reactive gas flow path is configured such that the connection path of the outlet side communication path portion is set to a size that is at least smaller in the width direction or depth direction than the connection path of the inlet side communication path portion. And fuel cell stack. The fuel cell stack according to claim 1 or 2, wherein the inlet-side communication path portion and the outlet-side communication path portion have a connection path provided in the separator,
In the first reaction gas flow path, the connection path of the outlet side communication path portion is set to have a larger cross-sectional area or shorter than the connection path of the inlet side communication path section,
The fuel cell, wherein the third reaction gas flow path is configured such that the connection path of the outlet side communication path is smaller in cross-sectional area or longer than the connection path of the inlet side communication path. stack.

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