JP4673110B2 - Fuel cell - Google Patents

Description

  In the present invention, an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are laminated, and a reactive gas is passed along the electrode surface between the electrolyte / electrode structure and the separator. A reaction gas channel to be supplied is formed, and a reaction gas inlet communication hole communicating with an inlet side of the reaction gas channel and a reaction gas outlet communication hole communicating with an outlet side of the reaction gas channel are stacked. The present invention relates to a fuel cell formed to penetrate in a direction.

  For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane made of a polymer ion exchange membrane. This fuel cell has an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode each made of an electrode catalyst (electrode catalyst layer) and porous carbon (diffusion layer) are provided on both sides of a solid polymer electrolyte membrane. The fuel cell is sandwiched between separators (bipolar plates). Usually, the fuel cell is used as a fuel cell stack in which a predetermined number of fuel cells are stacked.

  In the fuel cell described above, an internal manifold is often configured to supply a fuel gas and an oxidant gas, which are reaction gases, to the anode side electrode and the cathode side electrode of each stacked fuel cell. The internal manifold includes a reaction gas inlet communication hole and a reaction gas outlet communication hole that are provided to penetrate in the stacking direction of the fuel cell, and an inlet side of a reaction gas channel that supplies the reaction gas along the electrode surface, and The reaction gas inlet communication hole and the reaction gas outlet communication hole communicate with the outlet side.

For example, as shown in FIG. 9 , the separator disclosed in Patent Document 1 has a fuel gas flow channel groove portion 1 formed at the center, and a fuel gas is formed on the upper side of the fuel gas flow channel groove portion 1. An introduction manifold hole 2a, a cooling water introduction manifold hole 3a, and an oxidant gas introduction manifold hole 4a, 5a are provided. On the lower side of the fuel gas flow channel groove portion 1, oxidant gas discharge manifold holes 4b and 5b, a cooling water discharge manifold hole 3b, and a fuel gas discharge manifold hole 2b are provided.

  The fuel gas introduction manifold hole 2a is connected to the fuel gas flow channel groove portion 1 via a plurality of fuel gas flow grooves 6a, and the fuel gas flow groove 6a is closed with a solid polymer electrolyte membrane (not shown). In order to prevent this, the flat plate 7a is covered. The fuel gas discharge manifold hole 2b communicates with the fuel gas flow channel groove portion 1 through a plurality of fuel gas flow grooves 6b. The fuel gas flow groove 6b is covered with a flat plate 7b and is not shown in the figure. It is blocked by the electrolyte membrane.

  The width of the fuel gas flow groove 6a is formed larger than the groove width of the fuel gas flow path groove portion 1, and the cross sectional area of the fuel gas flow groove 6a is larger than the cross sectional area of the fuel gas flow path groove portion 1. It is getting bigger. The fuel gas flow groove 6b constituting the fuel gas discharge port has the same configuration as the fuel gas flow groove 6a.

  As a result, the widths of the fuel gas flow grooves 6a and 6b are widened, the fluid resistance of these portions can be reduced, and the fluid resistance of the fuel gas flow channel grooves 1 can be lowered to improve the power generation performance of the fuel cell. It can be done.

JP 2000-164227 A (FIG. 1)

  However, in Patent Document 1 described above, the flow velocity on the outlet side of the fuel gas flow channel groove portion 1 decreases, and the fuel gas flow groove 6b having a large cross-sectional area communicates with the outlet side, so that the flow velocity further decreases. Therefore, at the outlet of the fuel gas channel groove portion 1 of the specific cell, the drainage performance is lowered, and there is a possibility that the condensed water stays and the pressure loss increases. As a result, the flow of the reaction gas in the stack fluctuates, the stoichiometry of the reaction gas in the specific cell (reaction gas utilization rate) decreases, and the generation voltage decreases, causing the stack to generate electricity stably. There is a problem that you can not.

  The present invention solves this type of problem, and with a simple and economical configuration, it can reliably drain water from the reaction gas flow path to the reaction gas outlet communication hole, and perform efficient power generation. An object of the present invention is to provide a fuel cell capable of satisfying the requirements.

  In the present invention, an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are laminated, and a reactive gas is passed along the electrode surface between the electrolyte / electrode structure and the separator. A reaction gas channel to be supplied is formed, and a reaction gas inlet communication hole communicating with an inlet side of the reaction gas channel and a reaction gas outlet communication hole communicating with an outlet side of the reaction gas channel are stacked. It is a fuel cell formed penetrating in the direction.

  The outlet side of the reactive gas channel and the reactive gas outlet communication hole communicate with each other via a connecting passage, and the sectional opening area of the connecting passage is equal to the sectional opening area of the outlet side of the reactive gas channel. Smaller than.

  In addition, the electrolyte / electrode structure and the separator are stacked in the horizontal direction, while the outlet side of the reaction gas channel preferably extends in the horizontal direction. Communication holes can be provided at both ends in the horizontal direction of the separator, and the height of the stack can be kept low, which is particularly suitable for under-floor mounting.

  Furthermore, it is preferable that an outlet buffer part is provided on the outlet side of the reaction gas flow path, and the outlet buffer part has an inclined surface on the upper side. This is because water that tends to stay on the upper side can flow along the inclined surface.

  Furthermore, it is preferable that the reaction gas channel has a folded portion in the horizontal direction and the reaction gas flows from the upper side to the lower side. This is because the fluid length of the reaction gas channel is lengthened and the discharge of the produced water is improved.

  Further, the connecting passage is preferably provided near the lower part on the outlet side of the reaction gas channel. This is to prevent water droplets from staying on the lower side. Furthermore, it is preferable that the separator has a higher hydrophilicity in the passage surface of the connection passage than in the reaction gas passage. This is because water droplets do not stay and drainage is performed promptly.

  According to the present invention, the flow path opening cross-sectional area of the connection passage that communicates the outlet side of the reactive gas flow path and the reactive gas outlet communication hole is smaller than the flow path opening cross-sectional area of the outlet side. For this reason, the flow velocity of the reaction gas can be increased from the reaction gas channel toward the reaction gas outlet communication hole.

  Therefore, it is possible to satisfactorily prevent the staying water from existing on the outlet side of the reaction gas flow path, and the drainage can be further improved. Thereby, with a simple and economical configuration, a decrease in the reaction gas flow distribution due to an increase in pressure loss is suppressed, and stable power generation is performed efficiently.

  FIG. 1 is an exploded perspective view of a main part of a fuel cell 10 according to the first embodiment of the present invention, and FIG. 2 is a partial cross-sectional view of the fuel cell 10.

  The fuel cell 10 is formed by laminating an electrolyte membrane / electrode structure (electrolyte / electrode structure) 12 and first and second separators 14 and 16 in the horizontal direction (direction of arrow A). Configure the stack. The first and second separators 14 and 16 are made of, for example, a metal plate or a carbon plate.

  The electrolyte membrane / electrode structure 12 includes, for example, a solid polymer electrolyte membrane 18 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 20 and a cathode side electrode 22 that sandwich the solid polymer electrolyte membrane 18. With.

  The anode side electrode 20 and the cathode side electrode 22 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 platinum alloy on the surface. An electrode catalyst layer (not shown). The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 18.

  One end edge of the fuel cell 10 in the direction of arrow B communicates with each other in the direction of arrow A, which is the stacking direction, and an oxidant gas inlet communication hole (reactive gas) for supplying an oxidant gas, for example, an oxygen-containing gas. An inlet communication hole) 30a, a cooling medium inlet communication hole 32a for supplying a cooling medium, and a fuel gas outlet communication hole (reactive gas outlet communication hole) 34b for discharging a fuel gas, for example, a hydrogen-containing gas, Arranged in the C direction (vertical direction).

  The other end edge of the fuel cell 10 in the direction of arrow B communicates with each other in the direction of arrow A, discharges a fuel gas inlet communication hole (reaction gas inlet communication hole) 34a for supplying fuel gas, and discharges the cooling medium. A cooling medium outlet communication hole 32b for exhaust and an oxidant gas outlet communication hole (reaction gas outlet communication hole) 30b for discharging the oxidant gas are arranged in the direction of arrow C.

  As shown in FIGS. 1 to 3, a fuel gas flow path (reactive gas flow path) 36 is provided on a surface 14 a of the first separator 14 facing the electrolyte membrane / electrode structure 12. As shown in FIG. 3, the fuel gas flow channel 36 has a plurality of fuel gas flow channel grooves 36a, and the fuel gas flow channel grooves 36a meander in the direction of arrow C ( Specifically, a serpentine flow path is formed that bends in the direction of arrow B by one reciprocal half.

  Between the fuel gas flow path 36, the fuel gas inlet communication hole 34a, and the fuel gas outlet communication hole 34b, an inlet buffer part 38a and an outlet buffer part 38b having a plurality of embosses (or dimples) are provided. The fuel gas inlet communication hole 34a and the fuel gas outlet communication hole 34b communicate with the inlet buffer part 38a and the outlet buffer part 38b through connection passages 42a and 42b. In the connection passages 42a and 42b, bridge plates 43a and 43b are disposed along the seal line.

  Each of the connecting passages 42a and 42b has a plurality of passage grooves 44a and 44b extending in the horizontal direction (arrow B direction). The outlet side end 36b of the fuel gas channel groove 36a extends in the horizontal direction, and the flow path opening cross-sectional area of the connecting passage 42b is smaller than the flow path opening cross-sectional area of the outlet side end 36b. Is set.

  Specifically, as shown in FIGS. 3 and 4, the number of grooves on the outlet side end 36b is seven, whereas the number of grooves on the passage groove 44b constituting the connecting passage 42b is set to four. Is done. The passage groove 44b is preferably provided close to the lower portion of the outlet side end portion 36b. However, the passage groove 44b may be provided at equal intervals or at desired intervals within the width dimension in the arrow C direction of the outlet side end portion 36b. Good.

  The surface 14 a of the first separator 14 is set so that the passage surface of the connection passage 42 b is more hydrophilic than the flow passage surface of the fuel gas passage 36. As the hydrophilic treatment, for example, a solution in which a hydrophilic substance is mixed in a liquid medium is brought into contact with the passage surface of the connection passage 42b, or a hydrophilic coating film made of an organic compound or an inorganic compound is passed through the passage. In addition to being performed by forming on the road surface, various known methods are applied. The hydrophilicity is represented by a contact angle between the water droplet and the substance surface, and for example, a contact angle of 90 degrees or less is set.

  As shown in FIG. 5, an oxidant gas channel (reactive gas channel) 48 is provided on the surface 16 a of the second separator 16 facing the electrolyte membrane / electrode structure 12. The oxidant gas flow channel 48 has a plurality of oxidant gas flow channel grooves 48 a constituting a serpentine flow channel that is bent by one and a half reciprocations in the direction of arrow B, similarly to the fuel gas flow channel 36.

  Between the oxidant gas flow path 48, the oxidant gas inlet communication hole 30a, and the oxidant gas outlet communication hole 30b, an inlet buffer unit 50a and an outlet buffer unit 50b having a plurality of embosses (or dimples) are provided. The oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b communicate with the inlet buffer part 50a and the outlet buffer part 50b through connection passages 52a and 52b. Plate bodies 54a and 54b are disposed in the connection passages 52a and 52b along the seal line.

  The outlet side end 48b of the oxidant gas channel groove 48a extends in the horizontal direction, and the channel opening cross-sectional area of the connecting passage 52b is smaller than the channel opening cross-sectional area of the outlet side end 48b. Is set. Specifically, the number of channels (for example, 4) of the channel grooves 56b of the connecting channel 52b is reduced with respect to the number of channels (for example, 7) of the outlet side end portion 48b.

  The connecting passage 52b is preferably provided near the lower side of the outlet side end 48b. The surface 16 a of the second separator 16 is set such that the passage surface of the connection passage 52 b has higher hydrophilicity than the flow passage surface of the oxidant gas flow passage 48.

  The first separator 14 and the second separator 16 integrally form a cooling medium flow path 58 on the surfaces 14b, 16b facing each other (see FIG. 1). The cooling medium flow path 58 extends in the direction of arrow B, and communicates with the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b.

  As shown in FIGS. 1 to 3, on the surfaces 14 a and 14 b of the first separator 14, a first seal member 60 is provided around the outer peripheral edge of the first separator 14. A second seal member 62 is provided on the surfaces 16 a and 16 b so as to go around the outer peripheral edge of the second separator 16.

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

  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 34a. Further, a cooling medium such as pure water or ethylene glycol is supplied to the cooling medium inlet communication hole 32a.

  The oxidant gas is introduced into the oxidant gas flow path 48 of the second separator 16 from the oxidant gas inlet communication hole 30a. In the oxidant gas flow channel 48, as shown in FIG. 5, the oxidant gas is once introduced into the inlet buffer 50a and then dispersed in the plurality of oxidant gas flow channel grooves 48a. Therefore, the oxidant gas moves along the cathode side electrode 22 of the electrolyte membrane / electrode structure 12 while meandering through the respective oxidant gas flow channel grooves 48a.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 36 of the first separator 14 from the fuel gas inlet communication hole 34a. In the fuel gas channel 36, as shown in FIG. 3, the fuel gas is once introduced into the inlet buffer 38a and then dispersed in the plurality of fuel gas channel grooves 36a. Further, the fuel gas meanders through each fuel gas channel groove 36 a and moves along the anode side electrode 20 of the electrolyte membrane / electrode structure 12.

  Therefore, in the electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode side electrode 22 and the fuel gas supplied to the anode side electrode 20 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 22 is discharged from the outlet buffer 50b to the oxidant gas outlet communication hole 30b (see FIGS. 1 and 5). Similarly, the fuel gas consumed by being supplied to the anode electrode 20 is discharged from the outlet buffer portion 38b to the fuel gas outlet communication hole 34b (see FIG. 3).

  On the other hand, the cooling medium supplied to the cooling medium inlet communication hole 32a is introduced into the cooling medium flow path 58 formed between the first and second separators 14 and 16 (see FIG. 1). In the cooling medium flow path 58, the cooling medium cools over the entire power generation surface of the electrolyte membrane / electrode structure 12, and then is discharged to the cooling medium outlet communication hole 32b.

  In this case, in the first embodiment, as shown in FIGS. 3 and 4, the outlet side end portion 36b of the fuel gas flow path 36 is separated from the passage groove 44b constituting the connecting passage 42b via the outlet buffer portion 38b. It communicates with the fuel gas outlet communication hole 34b. At that time, the outlet side end portion 36b is approximately halved in the number of grooves (for example, seven to four) and communicates with the passage groove 44b, and the flow path opening cross-sectional area of the connecting passage 42b is the outlet side end portion. It is smaller than the channel opening cross-sectional area of the part 36b.

  For this reason, the flow velocity of the fuel gas discharged from the connection passage 42b toward the fuel gas outlet communication hole 34b can be increased. Therefore, the dew condensation water generated in the fuel gas flow path 36 and the generated water back-diffused from the cathode side electrode 22 are discharged from the fuel gas flow path 36 to the fuel gas outlet communication hole 34b in a good and reliable manner. It is possible to prevent the stagnant water from existing in the flow path 36.

  Thereby, in 1st Embodiment, drainage can be improved further, the fall of the flow velocity of the fuel gas by the increase in pressure loss is suppressed with a simple and economical structure, and efficient electric power generation is performed favorably. The effect that it becomes possible is acquired.

  Moreover, the connecting passage 42 b is provided near the lower portion of the outlet side end portion 36 b of the fuel gas passage 36. Accordingly, the water discharged from the outlet side end portion 36b to the outlet buffer portion 38b is easily and smoothly discharged to the fuel gas outlet communication hole 34b through the respective passage grooves 44b constituting the connection passage 42b, and the lower water droplets. Can be prevented.

  Furthermore, the passage surface of the connection passage 42 b is set to have higher hydrophilicity than the flow passage surface of the fuel gas flow passage 36. For this reason, there is an advantage that water does not form water droplets in the connection passage 42b, and drainage from the connection passage 42b to the fuel gas outlet communication hole 34b is further improved.

  Furthermore, the electrolyte membrane / electrode structure 12 and the first and second separators 14 and 16 are stacked in the horizontal direction, and the outlet side end portion 36b of the fuel gas outlet communication hole 34b is directed in the horizontal direction. It is extended. Accordingly, communication holes can be provided at both ends in the horizontal direction of the first and second separators 14 and 16, and the height of the fuel cell stack can be kept low, particularly when the fuel cell stack is mounted under the floor. It is suitable for.

  On the other hand, in the oxidant gas flow channel 48, as shown in FIG. 5, like the fuel gas flow channel 36, the connection passage 52b communicates with the outlet side end portion 48b with the number of flow channels approximately halved. Thereby, the same effect as the fuel gas flow path 36 is obtained.

  In the first embodiment, the number of grooves of the passage groove 44b of the connection passage 42b is reduced with respect to the number of grooves of the outlet side end portion 36b of the fuel gas passage 36. However, the present invention is not limited to this. is not. For example, the passage opening cross-sectional area of the connection passage 42b may be set small by configuring the passage grooves 44b to be the same number as the outlet side end portion 36b and narrower than the outlet side end portion 36b.

  FIG. 6 is an exploded perspective view of a main part of a fuel cell 80 according to the second embodiment of the present invention. The same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third embodiment described below, detailed description thereof is omitted.

  The fuel cell 80 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 82 and first and second separators (metal plates or carbon plates) 84 and 86 sandwiching the electrolyte membrane / electrode structure 82. Prepare.

  The electrolyte membrane / electrode structure 82 includes, for example, a solid polymer electrolyte membrane 88 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 90 and a cathode side electrode 92 that sandwich the solid polymer electrolyte membrane 88. With. The surface area of the anode side electrode 90 is set smaller than the surface area of the cathode side electrode 92.

  As shown in FIGS. 6 and 7, the first separator 84 is provided with a plurality of supply holes (connection passages) 94a in the vicinity of the fuel gas inlet communication hole 34a, while a plurality of supply holes (connection passages) 94a are provided in the vicinity of the fuel gas outlet communication hole 34b. A discharge hole (connection passage) 94b is provided. The flow path opening cross-sectional area of the discharge hole portion 94 b is set smaller than the flow path opening cross-sectional area of the outlet side end portion 36 b of the fuel gas flow path 36.

  Specifically, as shown in FIG. 7, the supply hole portions 94a are set to the same number as the fuel gas flow channel grooves 36a constituting the fuel gas flow channel 36, while the discharge hole portions 94b It is less than the number of grooves at the outlet side end 36b of the road groove 36a, and is set to, for example, half. For example, when the outlet side end portion 36b has six grooves, the number of the discharge hole portions 94b is set to three, and the discharge hole portion 94b approaches the lower portion of the outlet side end portion 36b. Provided. The surface 14 a of the first separator 84 is set so that the hole surface of the discharge hole portion 94 b is more hydrophilic than the flow channel surface of the fuel gas flow channel 36.

  In the fuel cell 80 configured as described above, the fuel gas moves from the fuel gas inlet communication hole 34 a to the surface 14 a side through the supply hole 94 a from the surface 14 b side of the first separator 84, and enters the fuel gas flow path 36. Supplied. The fuel gas moves vertically downward while meandering in the horizontal direction along the fuel gas flow path 36, and then is introduced into the surface 14b through the discharge hole portion 94b and discharged from the fuel gas outlet communication hole 34b. The

  At that time, the flow path opening cross-sectional area of the discharge hole portion 94 b is set smaller than the flow path opening cross-sectional area of the outlet side end portion 36 b of the fuel gas flow path 36. For this reason, the flow rate of the fuel gas which passes the discharge hole part 94b can be maintained high, and the effect similar to 1st Embodiment is acquired, such as improving drainage property.

  In the second embodiment, although not shown, a buffer portion may be provided between the supply hole portion 94a and the discharge hole portion 94b and the fuel gas flow path 36.

  FIG. 8 is an explanatory front view of the first separator 100 constituting the fuel cell according to the third embodiment of the present invention.

  The first separator 100 is provided with an outlet buffer portion 102 having a plurality of embosses (or dimples) between the fuel gas flow path 36 and the fuel gas outlet communication hole 34b. The outlet buffer portion 102 has an inclined surface 102a on the upper side, and in FIG. 8, water tends to stay in the upper right portion of the emboss, and the water flows smoothly along the inclination of the inclined surface 102a. Thereby, it is possible to more reliably prevent the stagnant water from being generated in the outlet buffer unit 102.

It is a principal part disassembled perspective view of the fuel cell which concerns on the 1st Embodiment of this invention. 2 is a partial cross-sectional view of the fuel cell. FIG. It is front explanatory drawing of the 1st separator which comprises the said fuel cell. It is a principal part perspective explanatory drawing of the exit side of a fuel gas flow path, and a connection channel | path. It is front explanatory drawing of the 2nd separator which comprises the said fuel cell. It is a principal part disassembled perspective view of the fuel cell which concerns on the 2nd Embodiment of this invention. It is front explanatory drawing of the 1st separator which comprises the said fuel cell. It is front explanatory drawing of the 1st separator which comprises the fuel cell which concerns on the 3rd Embodiment of this invention. It is explanatory drawing of the separator currently disclosed by patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 80 ... Fuel cell 12, 82 ... Electrolyte membrane electrode structure 14, 16, 84, 86, 100 ... Separator 18, 88 ... Solid polymer electrolyte membrane 20, 90 ... Anode side electrode 22, 92 ... Cathode side electrode 30a ... Oxidant gas inlet communication hole 30b ... Oxidant gas outlet communication hole 32a ... Cooling medium inlet communication hole 32b ... Cooling medium outlet communication hole 34a ... Fuel gas inlet communication hole 34b ... Fuel gas outlet communication hole 36 ... Fuel gas flow path 36a ... Fuel gas passage groove 36b, 48b ... Outlet side end 38a, 50a ... Inlet buffer part 38b, 50b, 102 ... Outlet buffer part 42a, 42b, 52a, 52b ... Connection passage 44a, 44b, 56b ... Passage groove 48 ... Oxidant gas channel 48a ... Oxidant gas channel groove 58 ... Cooling medium channel 94a ... Supply hole 94b ... Discharge hole

Claims (4)

And both sides are a pair of electrodes separator and the electrolyte electrode assembly disposed in the electrolyte is laminated in the horizontal direction, the between the electrolyte electrode assembly and the separator, and has a folded portion in the horizontal direction A reaction gas channel for supplying a reaction gas from the upper side to the lower side along the electrode surface is formed, a reaction gas inlet communication hole communicating with the inlet side of the reaction gas channel, and a horizontal direction of the reaction gas channel A reaction gas outlet communication hole communicating with the outlet side extending in the direction is a fuel cell formed so as to penetrate in the stacking direction,
The inlet side of the reactive gas flow path and the reactive gas inlet communication hole communicate with each other through the same number of inlet side connecting passages as the reactive gas flow path,
The outlet side of the reactive gas flow channel and the reactive gas outlet communication hole communicate with each other via an outlet side connecting passage,
It said outlet side connecting communication path, a fuel cell, characterized by being provided closer to the bottom of the outlet side of the set to less number than the number of the reaction gas channel and the reaction gas channel. The fuel cell according to claim 1 , wherein an outlet buffer portion is provided on an outlet side of the reaction gas flow path,
The fuel cell, wherein the outlet buffer portion has an inclined surface on an upper side. 3. The fuel cell according to claim 1, wherein the separator is set such that a passage surface of the outlet-side connection passage has higher hydrophilicity than a passage surface of the reaction gas passage. 4. The fuel cell according to claim 1, wherein the inlet side connecting passage and the outlet side connecting passage are a supply hole portion and a discharge hole portion that are formed through the separator. 5. Fuel cell.

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