JP2009009773A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell suitable for assuring a flow passage of a cooling medium without increasing the number of parts or a cell pitch. <P>SOLUTION: The fuel cell includes: a conductive porous body 10A provided with a flat surface arranged contacted with at least one electrode catalyst layer 7B of a MEA 7 as a catalyst-electrode structure and the other surface having a concave-convex groove shape 60A, and supplying a reaction gas of one side to the one electrode catalyst layer 7B; and a separator 8, as a conductive fluid shielding plate, provided with a concave-convex groove shape to be mutually contacted with the conductive porous body 10A and laminated on the conductive porous body 10A. A concave portion of the separator 8, formed on an opposite side of a contact surface with the conductive porous body 10A by the concave-convex groove shape, is formed as part of a flow passage (8B) of the cooling medium, or part of a flow passage (9A) supplying the reaction gas of the other side to the other electrode catalyst layer 7B. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell in which an electrolyte membrane / electrode structure provided with an electrode catalyst layer on each side of an electrolyte membrane and a separator are laminated with a conductive porous body interposed therebetween.

  2. Description of the Related Art Conventionally, a fuel cell using a conductive porous body as a reactive gas flow path portion has been proposed in order to reliably form a reactive gas flow path and reduce the size (see Patent Document 1).

In this method, a gas diffusion layer is provided on the anode side electrode and the cathode side electrode constituting the electrolyte membrane / electrode structure, and this gas diffusion layer is made conductive to reduce contact resistance and make the in-plane reaction distribution uniform. Formed of a foam made of a metallic material such as stainless steel, and impregnated with a resin flow path wall for forming a reaction gas flow path in the foam to form a reaction gas flow path portion. A fuel cell is configured by laminating metal separators.
JP 2004-87318 A

  By the way, a cooling medium that cools reaction heat generated by an electrochemical reaction of a fuel cell when a conductive porous body is used for a reaction gas flow path and stacked in combination with a flat separator as in the conventional example. Is configured to circulate in a space sandwiched between flat separators. In this case, it is necessary to secure a planar space region in the cell stacking direction for a total of three fluids, ie, two reaction gas fluids that are anode gas and cathode gas used in the fuel cell and one cooling medium fluid such as cooling water. In order to allow these fluids to flow uniformly with little pressure loss, the height in the stacking direction must be ensured in the planar space of each fluid, and the cell pitch becomes large.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a fuel cell suitable for securing a cooling medium flow path without increasing the cell pitch.

  The present invention has a flat surface disposed in contact with at least one electrode catalyst layer of an electrolyte / electrode structure, and has a concave and convex groove shape on the other surface so that one reaction gas is supplied to one electrode. A fuel cell comprising: a conductive porous body to be supplied to the catalyst layer; and a conductive fluid shielding plate having a concave and convex groove shape that is in contact with the conductive porous body and laminated on the conductive porous body, The concave portion formed on the opposite side of the contact surface with the conductive porous body due to the shape of the concave and convex grooves of the conductive fluid shielding plate, a part of the flow path of the cooling medium or the other reactive gas as the other electrode catalyst layer It was made to be a part of the flow path supplied to.

  Therefore, in the present invention, the conductivity is provided with a concave and convex groove shape on the back side arranged in contact with at least one electrode catalyst layer of the electrolyte / electrode structure, and supplies one reaction gas to one electrode catalyst layer. The porous body is provided with a conductive fluid shielding plate that has a concave and convex groove shape that is in contact with each other and is laminated on the conductive porous body, and the conductive fluid shielding plate and the conductive porous body are formed by the concave and convex groove shape of the conductive fluid shielding plate. The concave portion formed on the opposite side of the contact surface is a part of the flow path of the cooling medium or a part of the flow path for supplying the other reaction gas to the other electrode catalyst layer. For this reason, in one cross section in the stacking direction, the gas flow part and the refrigerant flow part share the cross-sectional area, and the refrigerant flow path can be secured without increasing the cell pitch and without adding new parts. it can.

  Hereinafter, the fuel cell of the present invention will be described based on each embodiment.

(First embodiment)
1 to 9 show a first example of a fuel cell according to a first embodiment to which the present invention is applied. FIG. 1 is a perspective view of a fuel cell stack formed by stacking fuel cells. FIG. 2 is a fuel cell. FIG. 3 and FIG. 4 are explanatory diagrams showing the shapes of the front surface (A) and the back surface (B) of each separator, FIG. 5 is a perspective view showing the stacked state of the fuel cells, FIG. 6 and FIG. 7 is a cross-sectional view showing each cross section of the fuel cell, FIG. 8 is an explanatory diagram of the cross-sectional state of the fuel cell, and FIG. 9 is a characteristic diagram showing the relationship between the reaction gas passage and the cell voltage.

  In FIG. 1, a fuel cell stack 1 formed by stacking fuel cells includes a current collector plate 3 and an insulating layer 4 on the outer side of a stack end where a plurality of fuel cells 2 are stacked, and an end plate on the outer side. 5 are stacked and arranged in this order. Tension plates 6 are bridged between the end plates 5 at the four corners, and end portions of the tension plates 6 are fixed to the end plates 5 with bolts 6A. A compression force (fastening load) is applied.

  As shown in FIG. 2, the fuel cell 2 includes an electrolyte membrane 7A made of an ion exchange membrane and a membrane / electrode assembly 7 (hereinafter referred to as “MEA”) made of a pair of electrode catalyst layers 7B sandwiching the electrolyte membrane 7A from both sides. ) And a pair of separators 8 and 9 sandwiched from the outside by interposing porous bodies 10A and 10B as gas diffusion layers having conductivity by being laminated on the electrode catalyst layer 7B of the MEA 7, respectively. ing. The pair of separators 8 and 9 is formed of a conductor whose base material is a metal material such as stainless steel, for example.

  As will be described later, the anode separator 8 constituting one of the pair of separators 8 and 9 is an anode such as hydrogen gas (H2) on the corresponding electrode catalyst layer 7B of the MEA 7 on the plate surface laminated adjacent to the MEA 7. A fuel gas flow path 8A for supplying gas (hereinafter referred to as "fuel gas") is provided, and a cooling medium for cooling the fuel cell (cooling water or the like, hereinafter referred to as "refrigerant") is provided on the back surface. A refrigerant flow path 8B is provided.

  The cathode separator 9 constituting the other is a cathode made of air (O2) or the like on the electrode catalyst layer 7B corresponding to the MEA 7 on the plate surface (back side in the figure) laminated adjacent to the MEA 7, as will be described later. An adjacent fuel cell which is provided with an oxidant gas flow path 9A for supplying gas (hereinafter referred to as “oxidant gas”) and is stacked adjacent to the side not facing the MEA 7 (front side in the figure). Between the back side of the anode separator 8 in the cell 2, a refrigerant flow path 9 </ b> B for flowing a refrigerant for cooling the fuel cell is provided.

  The oxidant gas and the fuel gas diffused by the porous bodies 10A and 10B and supplied to the electrode catalyst layers 7B cause an electrochemical reaction in the MEA 7 of the fuel cell 2 to generate an electromotive force. Further, the electrochemical reaction is an exothermic reaction, and a coolant for cooling the fuel cell (hereinafter referred to as “cooling water”) is provided in the coolant channels 8B and 9B provided on the anode separator 8 and the cathode separator 9 on the side not facing the MEA 7. To cool down.

  Further, the MEA 7, the anode separator 8 and the cathode separator 9 that constitute each of the fuel battery cells 2 are connected to the inlets of the gas passages 8 A and 9 A and the refrigerant passages 8 B and 9 B (for fuel gas and oxidant gas) and Manifold forming through holes 11A to 13A are formed which communicate with the outlets independently of each other. Although the drawing shows only the through hole for the inlet manifold, the through hole for the outlet manifold is also provided at the opposite end (not shown). In addition, although not shown, the current collecting plate 3 and the insulating layer 4 constituting the fuel cell stack 1 and the end plate 5 disposed on one side are similarly configured to the gas flow path 8A (for fuel gas and oxidant gas). , 9A and the inlets and outlets of the refrigerant flow paths 8B, 9B are formed through holes for forming manifolds.

  And when these are laminated | stacked as the fuel cell stack 1, these through-holes 11A-13A (and the through-hole for outlet manifolds) are piled up, and the inlet manifold 11 (and outlet manifold for fuel gas distribution) is piled up. ), An inlet manifold 13 (and an outlet manifold) for circulating the oxidant gas, and a refrigerant inlet manifold 12 (and an outlet manifold) are formed to penetrate in the cell stacking direction. These inlet manifolds 11 to 13 (and outlet manifolds) are provided with through holes 11A to 13A (and outlet manifold through holes) in the separators 9 and 10 and MEA 7, and the inlet manifolds 11 to 13 (and In the following, an example in which the internal manifold system is applied will be described.

  As shown in FIG. 1, introduction pipes 11C to 13C and discharge pipes 14C to 16C are arranged on the one end plate 5 as shown in FIG. 1 in connection with the open ends of the inlet manifolds 11 to 13 (and outlet manifolds). The fuel cells (fuel gas), the oxidant gas and the refrigerant are introduced into the corresponding inlet manifolds 11 to 13 through the inlet pipes 11C to 13C, and the fuel cells 2 pass through the outlet pipes 14C to 16C from the outlet manifolds. The fuel gas, oxidant gas and refrigerant that have not been consumed in the reaction are discharged.

  As shown in FIG. 3, the anode separator 8 has a plate surface facing the MEA 7 (see FIG. 3A) on the corresponding electrode catalyst layer 7B of the MEA 7 with a fuel such as hydrogen gas via the porous body 10A. A fuel gas flow path 8A formed by an uneven groove for supplying gas is provided. The fuel gas flow path 8A communicates with the fuel gas inlet manifold 11 via a flow distribution portion 20 formed of a flat portion extending in the plate width direction, and the fuel gas flows from the through hole 11A of the inlet manifold 11 to the flow distribution portion. 20 is distributed in the plate width direction and flows into each fuel gas flow path 8A.

  Although not shown in the drawing, the fuel gas that has not been consumed in the electrochemical reaction is communicated to the outlet manifold via a current collecting portion composed of a flat portion extending in the plate width direction. It is collected from the fuel gas flow path 8A by the collecting portion and discharged to the outlet manifold.

  The flow distribution portion 20 and the current collecting portion formed by the fuel gas flow path 8A and the flat portion formed by the concave and convex grooves are not formed in contact with the MEA 7 when stacked in the stacking direction as fuel cells. It is formed by parts. Further, on the plate surface (the side (A) in FIG. 3) facing the MEA 7 of the anode separator 8, the oxidant gas manifold 13 and the through holes 12 A and 13 A of the refrigerant inlet manifold 12 are respectively enclosed, and the fuel gas manifold 11 is provided. A linear seal 21 that seals the fuel gas is provided so as to surround the through holes 11A, the flow distribution portion 20, the fuel gas flow path 8A, the current collection portion (not shown), and the through holes of the outlet manifold.

  Further, on the back side (see FIG. 3 (B)) of the anode separator 8 that does not face the MEA 7, the fuel cell cooling is formed on the back side by the concave and convex grooves provided for forming the fuel gas flow path 8A. The refrigerant flow path 8B is provided for flowing the refrigerant. The refrigerant flow path 8B is connected to a refrigerant inlet manifold via a flow distribution section 30 formed of a plane portion (back side of the plane portion constituting the flow distribution section 20 formed on the front surface side) formed to expand in the plate width direction. 12 communicates. The refrigerant is distributed in the plate width direction from the through hole 12A of the inlet manifold 12 by the flow distribution section 30, and flows into each refrigerant flow path 8B (9B). Although not shown, the downstream of each refrigerant flow path 8B (9B) communicates with the outlet manifold via a current collecting portion formed by a flat portion extending in the plate width direction, and passes through the refrigerant flow path 8B (9B). The collected refrigerant is collected by the collecting portion and discharged to the outlet manifold.

  The refrigerant flow path 8B formed by the concave and convex grooves is a concave and convex groove in which the edge portions of the refrigerant flow path 9B formed by the concave and convex grooves of the cathode separator 9 to be described later come into contact when stacked as fuel cells. Further, on the plate surface (the (B) side in FIG. 3) of the anode separator 8 that does not face the MEA 7, the through holes 11A and 13A of the fuel gas manifold 11 and the oxidant gas manifold 13 are respectively enclosed, and the refrigerant inlet manifold 12 is provided. Further, a linear seal 31 is provided to seal the refrigerant by surrounding the through hole of the flow distributor 30, the refrigerant flow path 8 </ b> B, the current collector (not shown) and the outlet manifold.

  As shown in FIG. 4, the cathode separator 9 has a plate surface facing the MEA 7 (see FIG. 4B) on the corresponding electrode catalyst layer 7B of the MEA 7 with an oxidant such as air through the porous body 10B. An oxidant gas flow path 9A formed by concave and convex grooves for supplying gas is provided. The oxidant gas flow path 9A communicates with the oxidant gas inlet manifold 13 via a flow distribution portion 40 formed of a flat surface portion extending in the plate width direction, and the oxidant gas passes through the through hole 13A of the inlet manifold 13. Are distributed in the plate width direction by the flow distribution section 40 and flow into the oxidant gas flow paths 9A.

  Although not shown, downstream of each oxidant gas flow path 9A is communicated with the outlet manifold via a current collecting portion formed of a flat portion extending in the plate width direction, and the oxidant that has not been consumed in the electrochemical reaction. The gas is collected from the oxidant gas flow path 9A by the collecting portion and discharged to the outlet manifold.

  The flow distribution part 40 and the current collecting part formed by the oxidant gas flow path 9A formed by the concave and convex grooves and the flat surface portion have a concave and convex groove having a depth that does not come into contact with the MEA 7 when stacked in the stacking direction as fuel cells. It is formed by a flat portion. Further, the plate surface facing the MEA 7 of the cathode separator 9 (the (B) side in FIG. 4) surrounds the through holes 11A and 12A of the fuel gas manifold 11 and the refrigerant inlet manifold 12, and the oxidant gas manifold 13 respectively. A linear seal 41 that seals the oxidant gas is provided so as to surround the through hole 13A, the distribution portion 40, the oxidant gas flow path 9A, the current collector (not shown), and the through hole of the outlet manifold.

  Further, on the back side of the cathode separator 9 that does not face the MEA 7 (see FIG. 4A), the fuel cell cooling formed on the back side by the concave and convex grooves provided for the formation of the oxidant gas flow path 9A. The refrigerant flow path 9B for flowing the refrigerant for use is provided. The refrigerant flow path 9B is connected to a refrigerant inlet manifold via a flow distribution section 50 formed by a plane portion (back side of the plane portion constituting the flow distribution section 40 formed on the front surface side) formed so as to expand in the plate width direction. 12 communicates. The refrigerant is distributed in the plate width direction from the through hole 12A of the inlet manifold 12 by the distribution section 50 and flows into each refrigerant flow path 9B (8B). Although not shown, the downstream of each refrigerant flow path 9B (8B) communicates with the outlet manifold through a current collecting portion formed by a flat portion extending in the plate width direction, and passes through the refrigerant flow path 9B (8B). The collected refrigerant is collected by the collecting portion and discharged to the outlet manifold.

  The refrigerant flow path 9B formed by the concave and convex grooves is a concave and convex groove in which the edge portions of the refrigerant flow path 8B formed by the concave and convex grooves of the anode separator 8 are in contact with each other when stacked as fuel cells in the stacking direction. . Further, on the plate surface (the (A) side in FIG. 4) of the cathode separator 9 that does not face the MEA 7, instead of the linear seal 31 provided on the back surface of the anode separator 8, the fuel gas manifold 11 and the oxidant gas manifold 13 are provided. A line for sealing the refrigerant by surrounding the through holes 11A and 13A and surrounding the through holes 12A of the refrigerant inlet manifold 12, the flow distribution section 50, the refrigerant flow path 9B, the current collecting section (not shown) and the through holes of the outlet manifold. A shaped seal 51 may be provided.

  In addition, the cathode separator 9 has a plurality of regions (one in the figure) reaching a region overlapping one end of the through hole 12A of the refrigerant inlet manifold 12 and the refrigerant distribution portion 30 provided on the back surface of the anode separator 8 where the other end is overlapped. Then, three convex grooves are provided so as to protrude from the back surface side (FIG. 4A side) of the cathode separator 9 toward the front surface side (FIG. 4B side). The space in the convex groove forms a refrigerant introduction passage 52 that allows the refrigerant inlet manifold 12 </ b> A and the refrigerant distribution portion 30 of the anode separator 8 to communicate with each other when the anode separator 8 and the back surface overlap each other. Although not shown, a refrigerant discharge passage that connects the outlet manifold and the refrigerant collecting portion provided on the back surface of the anode separator when overlapped with the anode separator is also formed on the refrigerant outlet manifold side with the same configuration. The

  The height of the convex groove is such that the cathode separator 9 is in contact with the surface of the MEA 7 when the cathode separator 9 is laminated with the MEA 7, that is, the surface where the anode separator 8 and the back surface of the cathode separator 9 are brought into contact with each other. And the surface of the MEA 7 (in this example, the thickness of the linear seal 41 in a state where a lamination load is applied) is set. The convex grooves are formed as a plurality of convex grooves on the surface side of the cathode separator 9 (see FIG. 4B). However, on this surface side, the refrigerant inlet manifold 12 and the plurality of convex grooves are: It is surrounded by a linear seal 41 and is sealed so as to be separated from the oxidant gas inlet manifold 13, the distribution section 40, the fuel gas inlet manifold 11, and the like. Although not shown, the refrigerant discharge passage and the linear seal 41 on the refrigerant outlet manifold side are also formed in the same configuration.

  A porous body 10A as a gas diffusion layer disposed between the anode separator 8 and the MEA 7 is formed of a porous material of a conductive material, and has a concave-convex shape on the side facing the anode separator 8, as shown in FIG. 60A, and a substantially flat planar shape 60B on the side facing the MEA 7. The uneven shape 60 </ b> A has a shape corresponding to the uneven shape forming the fuel gas flow path 8 </ b> A of the anode separator 8. At the time of stacking, the fuel gas flow path portion 8A of the anode separator 8 and the concavo-convex shape 60A of the porous body 10A are fitted to each other, and the porous body 10A contacts the anode separator 8 over the entire surface. Further, the porous body 10A is in contact with the MEA 7 with a substantially flat planar shape 60B at the time of lamination, and the porous body 10A is in contact with the MEA 7 over the entire surface.

  In addition, the porous body 10B as a gas diffusion layer disposed between the cathode separator 9 and the MEA 7 is also formed of a porous material of a conductive material, and has a concavo-convex shape 61A on the side facing the cathode separator 9, A substantially flat planar shape 61B is provided on the side facing the MEA 7. The concave / convex shape 61 </ b> A is formed in a shape corresponding to the concave / convex shape forming the oxidizing gas channel 9 </ b> A of the cathode separator 9. At the time of lamination, the oxidant gas flow path 9A of the cathode separator 9 and the uneven shape 61A of the porous body 10B are fitted to each other, and the porous body 10B contacts the cathode separator 9 over the entire surface. Further, the porous body 10B comes into contact with the MEA 7 in a substantially flat planar shape 61B at the time of stacking, and the porous body 10B comes into contact with the MEA 7 over the entire surface.

  The anode separator 8 and the cathode separator 9 are laminated with the side surfaces shown in FIG. 6 opposite to the side on which the porous bodies 10A and 10B are laminated, in contact with each other. Then, when the porous bodies 10A and 10B and the MEA 7 are sequentially laminated on the laminated separators 8 and 9, they are laminated as shown in FIG. In FIG. 7, the respective cross-sections of OO, PP, QQ, and RR are shown with reference to the separators 8 and 9 of FIG. 8 stacked adjacent to each other. Further, FIG. 7 shows a case where separators 8 and 9 of fuel cells adjacent to each other are arranged at the center and MEA 7 of fuel cells is arranged at both ends, and contact of any of these separators 8 and 9 is shown. Illustration of the linear seals 31 and 51 provided on the surface is omitted.

  In FIG. 7, between the separators 8 and 9 stacked adjacent to each other, as shown in a cross section OO, introduction passages 52 are formed by a plurality of convex grooves on the cathode separator 9 side that lead to the refrigerant inlet manifold 12. As shown in the cross section PP, the introduction passage 52 communicates with a space extending in the width direction formed by the flow distribution portion 30 on the back surface of the anode separator 8 and the back surface of the cathode separator 9. The space expanded in the width direction is also expanded in the stacking direction by the flow distribution portion 50 provided on the back surface of the cathode separator 9 as shown in the cross section QQ. The separators 8 and 9 are configured to communicate with a refrigerant flow path 8B (9B) formed by concave and convex grooves formed on the back surfaces of the separators 8 and 9.

  Accordingly, the refrigerant supplied from the inlet manifold 12 is first introduced from the introduction passage 52 shown in the section OO in the width direction formed by the flow distribution section 30 of the anode separator 8 and the back surface of the cathode separator 9 shown in the section PP. It flows into the expanded space and is distributed in the width direction, and then spreads in the stacking direction by the distribution portions 30 and 50 of both separators 8 and 9. And it will flow into refrigerant flow path 8B (9B) formed between both separators 8 and 9 shown in section RR.

  The refrigerant flowing into each refrigerant flow path 8B (9B) absorbs reaction heat transmitted through the separators 8 and 9 and the porous bodies 10A and 10B to cool the reaction surface of the fuel cell, and each refrigerant flow path. From 8B (9B), the gas flows into a current collecting portion (not shown) formed in the same manner as the cross sections QQ and PP, and enters the outlet manifold via a discharge passage (not shown) formed in the same manner as the cross section OO. As a result, the fuel cell stack 1 is discharged.

  On the other hand, the fuel gas supplied to the inlet manifold 11 is supplied from the inlet manifold 11 to the distribution section 20 having a cross section PP (and a cross section QQ), spreads in the width direction at the distribution section 20, and has a cross section RR. Flows into the space between the fuel gas flow path 8A and the MEA 7 of the anode separator 8 shown, diffused by the porous body 10A arranged in this space, supplied to the electrode catalyst layer 7B of the MEA 7, and on the other surface of the MEA 7 Electrochemical reaction with the oxidant gas supplied to the electrode catalyst layer 7B. The fuel gas not consumed in the reaction is collected from the other end of the porous body 10A by a collecting portion (not shown), reaches the outlet manifold, is discharged out of the fuel cell stack 1, is recirculated, and is supplied to the inlet manifold 11. Is done.

  The oxidant gas supplied to the inlet manifold 13 is supplied from the inlet manifold 13 to the distribution section 40 having a cross section Q-Q, spreads in the width direction at the distribution section 40, and oxidizes the cathode separator 9 shown by a section RR. Flows into the space between the agent gas flow path 9A and the MEA 7, is diffused by the porous body 10B disposed in this space, is supplied to the other electrode catalyst layer 7B of the MEA 7, and the electrode catalyst layer on the other surface of the MEA 7 Electrochemical reaction with fuel gas supplied to 7B. The oxidant gas that has not been consumed in the reaction is collected from the other end of the porous body 10B by a collecting portion (not shown), reaches an outlet manifold, and is discharged out of the fuel cell stack 1.

  By the way, the setting of the groove width dimension C of the fuel gas flow path 8A and the oxidant gas flow path 9A, the groove width dimension A of the rear refrigerant flow path, and the height dimension B of the concave and convex grooves by the concave and convex grooves provided in the anode separator 8 is set. A method will be described. FIG. 8 shows the groove width dimension C of the fuel gas flow path 8A and the groove width dimension A of the back surface refrigerant path by the concave and convex grooves of the anode separator 8, and the concave and convex groove depth dimension B and the convex portions of the concave and convex grooves. It is the figure which showed the relationship of the thickness dimension D of the electroconductive porous body between MEA7.

  In FIG. 8, first, in the refrigerant flow path 8A (9B) formed between the anode separator 8 and the cathode separator 9, the necessary cross-sectional area of the refrigerant flow path 8A (9B) is determined from the viewpoint of the pressure loss of the refrigerant. Then, the groove width dimension C of the fuel gas passage 8A, the groove width dimension A of the rear refrigerant passage 8B (9B), and the height dimension B of the concave and convex grooves are determined.

  In addition, when the groove width dimension A of the refrigerant flow path is fixed and the flow rate of the supplied fuel gas is constant, the thickness dimension D of the conductive porous body 10A between the convex part of the concave-convex groove and the MEA 7 and the fuel The relationship between the cell voltages that can be generated in the battery cell is the characteristic shown in FIG. That is, as the thickness dimension D of the conductive porous body 10A between the convex portion of the concave-convex groove to the MEA 7 decreases, as a reaction gas to the region of the electrode catalyst layer 7B of the MEA 7 that overlaps with the convex portion of the concave-convex groove when stacked. Since the supply of the fuel gas is reduced, the distribution of the supply amount of the fuel gas in the surface of the electrode catalyst layer is likely to be uneven, and the cell voltage is lowered as a whole.

  And as the fuel cell stack 1, the minimum thickness dimension D of the conductive porous body 10A between the convex part of the concave-convex groove and the MEA 7 in which performance equal to or higher than the cell voltage that requires power generation in each individual fuel battery cell 2 is secured. Determine the dimensions. That is, in the present embodiment, the groove width dimension A (and height dimension B) of the refrigerant flow path 8B (9B) is determined from the viewpoint of securing the flow rate of the refrigerant flow path 8A (9B), and then the convexity of the concave and convex grooves is determined. The thickness D of the conductive porous body between the part and the MEA 7 is determined, and these dimensions are sufficient as long as the fuel gas can be sufficiently supplied to the entire surface of the electrode catalyst layer.

  In the fuel cell configured as described above, when the conductive porous body 10A or 10B is used for at least one of the fuel gas flow path 8A or the oxidant gas flow path 9A, the electrode catalyst of the porous bodies 10A and 10B is used. An uneven groove having a thickness equal to or less than that of the porous bodies 10A and 10B is provided on the side opposite to the surface in contact with the layer 7B, and a separator 8 or 9 as a gas shielding plate having an uneven shape corresponding to the uneven groove is disposed. Refrigerant as another fluid flows on the back side of the 8 or 9 uneven grooves. Therefore, in one cross section in the stacking direction, the gas flow portion and the refrigerant flow portion share the cross-sectional area, and the refrigerant flow path 8B (9B) is secured without increasing the cell pitch and without adding new parts. can do.

  In the above-described embodiment, the cathode separator 9 is described as having substantially straight irregularities similar to the anode separator 8. However, the shape is not particularly limited, and when the fuel cells 2 are stacked, a space in which the refrigerant flows into a space sandwiched between the anode separator 8 and the cathode separator 9 is formed from the inlet manifold 12 to the outlet manifold. Good.

  Moreover, in the said embodiment, what flows a refrigerant | coolant was demonstrated as a fluid flowed to the back surface part of the anode separator 8. FIG. However, although not shown, the oxidizing gas as the other reaction gas may be part of the oxidizing gas channel 9A that supplies the other electrode catalyst layer 7B.

  In the present embodiment, the following effects can be achieved.

  (A) While having a flat surface arranged in contact with at least one electrode catalyst layer 7B of the MEA 7 as an electrolyte / electrode structure, the other surface has an uneven groove shape 60A, and one reaction gas As a conductive fluid shielding plate that is laminated on the conductive porous body 10A with a conductive porous body 10A that supplies the electrode to one electrode catalyst layer 7B and an uneven groove shape that contacts the conductive porous body 10A. The separator 8 is a fuel cell, and a recess formed on the opposite side of the contact surface with the conductive porous body 10A due to the shape of the concave and convex grooves of the separator 8 is formed in the flow path of the cooling medium (8B). A part or the other reaction gas is used as a part of the channel (9A) for supplying the other electrode catalyst layer 7B. For this reason, in one cross section in the stacking direction, the gas flow portion and the refrigerant flow portion share the cross-sectional area, and the refrigerant flow path 8B is formed without increasing the cell pitch and without adding new parts such as spacers. Can be secured.

  (A) An MEA 7 as an electrolyte / electrode structure configured by sandwiching an electrolyte membrane 7A between a pair of electrode catalyst layers 7B, and a flat surface 60B arranged in contact with one electrode catalyst layer 7B of the MEA 7 are provided. At the same time, the other surface is provided with an uneven groove shape 60A, and the first conductive porous body 10A for supplying one reaction gas to one electrode catalyst layer 7B and the first conductive porous body 10A are mutually connected. An anode separator 8 as a first conductive fluid shielding plate that is laminated on the first conductive porous body 10A with a concave and convex groove shape that is in contact with the other electrode catalyst layer 7B of the MEA 7 A second conductive porous body 10B provided with a flat surface 61B to be disposed, and provided with an uneven groove shape 61A on the other surface, and supplying the other reaction gas to the other electrode catalyst layer 7B; 2 conductive porosity A cathode separator 9 as a second conductive fluid shielding plate that is laminated on the second conductive porous body 10B with an uneven groove shape contacting each other with 10B, and the anode separator 8 and the cathode By forming recesses formed on the opposite side of the contact surface with the conductive porous bodies 10A and 10B due to the shape of the concave and convex grooves of the separator 9, a cooling medium flow path 8B (9B) is obtained, whereby fuel gas and oxidant The gas flow path and the refrigerant flow path 8B (9B) of the gas share the cross-sectional area of the gas flow portion and the refrigerant flow portion, and add new parts without increasing the cell pitch. Therefore, the refrigerant flow path 8B can be secured.

(Second Embodiment)
10 and 11 show a second embodiment of the fuel cell to which the present invention is applied, FIG. 10 is an exploded perspective view of the fuel cell, and FIG. 11 is a perspective view showing the stacked state of the fuel cell. In this embodiment, a configuration in which a conductive porous body is disposed only between the cathode separator and the MEA and no porous body is disposed between the anode separator and the MEA is added to the first embodiment. In addition, the same code | symbol is attached | subjected to the same apparatus and member as 1st Embodiment, and the description is abbreviate | omitted or simplified.

  In FIG. 10, on the MEA 7 side of the cathode separator 9, similarly to the first embodiment, the conductive porous body 10 </ b> B is installed by fitting the concavo-convex shape 61 </ b> A into the oxidizing gas channel 9 </ b> A having the concavo-convex groove, The porous body 10B contacts the cathode separator 9 over the entire surface. Further, the porous body 10B comes into contact with the MEA 7 in a substantially flat planar shape 61B at the time of stacking, and the porous body 10B comes into contact with the MEA 7 over the entire surface.

  Further, the porous gas 10A is not interposed on the MEA 7 side of the anode separator 8 as in the first embodiment, and the fuel gas flow path 8A directly faces the MEA 7, and the fuel gas flow of the anode separator 8 is It is set as the structure which contacts MEA7 the front-end | tip of the convex part of the uneven groove | channel which comprises the path 8A.

  In the present embodiment, the side of the cathode separator 9 where the conductive porous body 10B is installed is the oxidant gas flow path 9A, and the side where the anode separator 8 directly faces and contacts the MEA 7 is the fuel gas flow path 8A. This is because the reaction gas supplied between the anode separator 8 and the MEA 7 is a fuel gas channel 8A (and a refrigerant channel) by supplying a fuel gas (H2) having high gas diffusibility and low fluid pressure loss. The height of the concave-convex groove of 8B) can be set lower. Note that lowering the height of the concave and convex grooves means that the flow passage cross-sectional area of the refrigerant flow passage 8B on the anode separator 8 side is reduced.

  On the other hand, on the cathode separator 9 side, in order to complement the cross-sectional area of the refrigerant flow path 8B reduced on the anode separator 8 side, the height of the concave and convex grooves constituting the oxidant gas flow path 9A and the refrigerant flow path 9B is increased. Even if the oxidant gas has a relatively low diffusivity, since the conductive porous body 10B is installed between the MEA 7 and the oxidant gas, a sufficient amount of gas is applied over the entire area of the opposing electrode catalyst layer. Supply becomes possible.

  Therefore, in this embodiment, the cell pitch can be further reduced by directly contacting the anode separator 8 and the MEA 7 without providing a conductive porous body.

  In the above-described embodiment, the concavo-convex groove facing the MEA 7 of the anode separator 8 has a linear concavo-convex shape similar to the anode separator 8 of the first embodiment. However, the shape is not particularly limited, and it is only necessary that a space in which the refrigerant flows is formed in a space between the cathode separator 9 and the anode separator 8 when the fuel cells 2 are stacked.

  In the present embodiment, in addition to the effect (a) in the first embodiment, the following effects can be achieved.

  (C) A flat surface 61B disposed in contact with the electrode catalyst layer 7B of the oxidant electrode of the MEA 7 as an electrolyte / electrode structure is provided, and the other surface is provided with a concave-convex groove shape 61A. A conductive porous body 10B that supplies gas to the electrode catalyst layer 7B of the oxidant electrode, and a first groove that is laminated on the conductive porous body 10B with an uneven groove shape that contacts the conductive porous body 10B. A cathode separator 9 as a conductive fluid shielding plate and an uneven groove shape that forms a flow path for supplying fuel gas to the electrode catalyst layer 7B of the fuel electrode of the MEA 7 and the uneven portion of the uneven groove shape are formed on the fuel electrode of the MEA 7 And an anode separator 8 as a second conductive fluid shielding plate disposed in contact with the electrode catalyst layer 7B of the first and second separators 8 and 9, and formed on the back surface by the uneven groove shape. Recess Even when the conductive porous body 10B is installed only on one side by forming the cooling medium flow path 8B (9B), the side where the anode separator 8 is in contact with the MEA 7 (the one without the porous body) The cell pitch can be further reduced by making the fuel gas flow path 8A with good diffusibility and small fluid pressure loss and directly contacting them without providing a conductive porous body.

(Third embodiment)
12 to 16 show a third embodiment of the fuel cell to which the present invention is applied, FIG. 12 is an exploded perspective view of the fuel cell, and FIG. 13 is the shape of the front surface (A) and the back surface (B) of the cathode separator. FIG. 14 is a perspective view showing the stacked state of the fuel cells, and FIGS. 15 and 16 are explanatory views showing cross sections of the fuel cells. In the present embodiment, a configuration in which the oxidant gas flow path of the cathode separator is formed in a planar shape is added to the first embodiment. In addition, the same code | symbol is attached | subjected to the same apparatus and member as 1st Embodiment, and the description is abbreviate | omitted or simplified.

  12 and 13, in the cathode separator 9 of the present embodiment, the oxidant gas flow path 9A and the refrigerant flow path 9B configured on the back surface thereof are formed in a flat shape instead of the concave and convex grooves. Further, the oxidant gas distribution part 40 and the refrigerant distribution part 50 formed on the back surface are also formed in the same plane as the oxidant gas flow path 9A and the refrigerant flow path 9B formed on the back surface thereof. Therefore, a plurality of (three in the figure) convex grooves are formed on the cathode separator 9 by cutting and raising from the back side (FIG. 13A) side to the front side (FIG. 13B side) of the cathode separator 9. Only the refrigerant introduction passage 52 is provided so as to protrude from the planar portion in the space in the convex groove so as to communicate with the refrigerant inlet manifold 12 and the refrigerant distribution portion 30 of the anode separator 8. Yes. Other cathode separators 9 are configured in the same manner as in the first embodiment.

  Further, as shown in FIG. 14, the conductive porous body 10B laminated between the cathode separator 9 and the MEA 7 has a substantially flat planar shape 62A on the side facing the cathode separator 9, and the MEA 7 On the opposite side, a substantially flat planar shape 62B is provided. Other configurations of the anode separator 8, the conductive porous body 10A, and the MEA 7 are the same as those in the first embodiment.

    The anode separator 8 and the cathode separator 9 are laminated by bringing the side surfaces (rear surfaces) shown in FIG. 15 opposite to the side on which the porous bodies 10A and 10B are laminated into contact with each other. Then, when the porous bodies 10A and 10B and the MEA 7 are sequentially laminated on the laminated separators 8 and 9, they are laminated as shown in FIG. In FIG. 16, the cross-sections of OO, PP, QQ, and RR are shown with reference to the separators 8 and 9 of FIG. FIG. 16 shows a configuration in which the separators 8 and 9 of the fuel cells 2 adjacent to each other are arranged at the center, and the MEAs 7 of the fuel cells 2 are arranged at both ends, and any one of these separators 8 and 9 is shown. Illustration of the linear seals 31 and 51 provided on the contact surface is omitted.

  In FIG. 16, between the separators 8 and 9 stacked adjacent to each other, as shown in a cross section OO, introduction passages 52 are formed by a plurality of convex grooves on the cathode separator 9 side that lead to the refrigerant inlet manifold 12. As shown in the cross section PP, the introduction passage 52 communicates with a space extending in the width direction formed by the flow distribution portion 30 on the back surface of the anode separator 8 and the back surface of the cathode separator 9. The space expanded in the width direction is shown in the section RR without being expanded in the stacking direction by the flow distribution portion 50 provided on the back surface of the cathode separator 9 as shown in the section QQ. Thus, it is configured to communicate with the refrigerant flow path 8B (9B) by the concave and convex grooves formed on the back surface of the anode separator 8.

  Accordingly, the refrigerant supplied from the inlet manifold 12 first passes through the introduction passage 52 shown in the section OO between the flow distribution section 30 of the anode separator 8 and the rear surface of the cathode separator 9 shown in the sections PP and QQ. It flows into the formed space extending in the width direction and is distributed in the width direction, and then flows into the refrigerant flow path 8B (9B) formed between the separators 8 and 9 shown in the section RR.

  On the other hand, the fuel gas supplied to the inlet manifold 11 is supplied from the inlet manifold 11 to the distribution section 20 having a cross section PP (and a cross section QQ), spreads in the width direction at the distribution section 20, and has a cross section RR. Flows into the space between the fuel gas flow path 8A and the MEA 7 of the anode separator 8 shown, diffused by the porous body 10A arranged in this space, supplied to the electrode catalyst layer 7B of the MEA 7, and on the other surface of the MEA 7 Electrochemical reaction with the oxidant gas supplied to the electrode catalyst layer 7B.

  The oxidant gas supplied to the inlet manifold 13 is supplied from the inlet manifold 13 to the distribution section 40 having a cross section Q-Q, spreads in the width direction at the distribution section 40, and oxidizes the cathode separator 9 shown by a section RR. Flows into the space between the agent gas flow path 9A and the MEA 7, is diffused by the porous body 10B disposed in this space, is supplied to the other electrode catalyst layer 7B of the MEA 7, and the electrode catalyst layer on the other surface of the MEA 7 Electrochemical reaction with fuel gas supplied to 7B.

  The fuel cell having the above-described configuration includes the porous body 10B having the substantially flat flat surface 10B, the oxidant gas flow path 9A on the space side between the cathode separator 9 and the MEA 7, and the porous body 10A having the concave and convex grooves. A fuel gas flow path 8A is provided on the space side between the separator 8 and the MEA 7. That is, by forming one separator (9) in a substantially flat plane, it is possible to reduce the thickness of the separator (9) on one side without requiring processing of the concave and convex grooves, so that the separator (9) can be made more MEA7. They can be arranged close to each other, and the cell pitch can be reduced accordingly.

  In addition, since the separator (9) on one side is a flat plane, the width of the concave and convex grooves of the refrigerant flow path 8B is secured in order to secure the cross-sectional area of the refrigerant flow path 8B in the concave and convex portion of the other separator (8). Since A and depth B are determined, in order to reduce the cell pitch, it is desired to make the thickness dimension D of the conductive porous body 10A between the protrusions of the concave and convex grooves of the separator (8) to the MEA 7 as small as possible. In this case, the fuel gas (H2) having a relatively high diffusivity and a small fluid pressure loss is supplied between the anode separator 8 having the fuel gas flow path 8A by the concave and convex grooves and the MEA 7, thereby oxidizing. Compared with the case where the agent gas is supplied, the thickness dimension D of the conductive porous body 10A between the convex portions of the concave and convex grooves of the separator (8) to the MEA 7 can be set smaller.

  That is, in this embodiment, the porous bodies 10A and 10B are stacked and installed on both electrode catalyst layers 7B, and one porous body 10A comes into contact with the separator (8) by the uneven shape 60A, and the other porous body 10B has Although it is in contact with the separator (9) by the flat plate shape 62A, it is porous while ensuring the cross-sectional area of the refrigerant flow path 8B by flowing a fuel gas with low fluid pressure loss on the one porous body 10A side having an uneven shape. The thickness of the body 10A can be reduced, and the cell pitch can be reduced.

  In the present embodiment, in addition to the effect (a) in the first embodiment, the following effects can be achieved.

  (D) A flat surface 60B disposed in contact with the electrode catalyst layer 7B of the fuel electrode of the MEA 7 as an electrolyte / electrode structure is provided, and the other surface is provided with a concave-convex groove shape 60A, and a fuel gas is provided. The first conductive porous body 10A to be supplied to the electrode catalyst layer 7B of the fuel electrode and the concave / convex groove shape that contacts the first conductive porous body 10A are laminated on the conductive porous body 10A. An anode separator 8 as a first conductive fluid shielding plate, a flat surface 62B disposed in contact with the electrode catalyst layer 7B of the oxidant electrode of the MEA 7 and a flat surface 62A on the other side, A second conductive porous body 10B that supplies an oxidant gas to the electrode catalyst layer 7B of the oxidant electrode, and a second conductive fluid shield that is laminated in contact with the second conductive porous body 10B. A cathode separator 9 as a plate; A back surface of the anode separator 8 and the cathode separator 9 are brought into contact with each other, and a concave portion formed on the opposite side of the contact surface with the first conductive porous body 10A due to the uneven groove shape of the anode separator 8; By forming the cooling medium flow path 8B (9B), a fuel gas with a low fluid pressure loss is caused to flow on the side of the porous body 10A having an uneven shape, thereby ensuring a cross-sectional area of the refrigerant flow path 8B. The thickness of the body 10A can be reduced, and the cell pitch can be reduced.

1 is a perspective view of a fuel cell stack configured by stacking fuel cells according to an embodiment of the present invention. The disassembled perspective view of a fuel cell similarly. Explanatory drawing which shows the shape of the surface (A) and back surface (B) of an anode separator. Explanatory drawing which shows the shape of the surface (A) and back surface (B) of a cathode separator. The perspective view which similarly shows the lamination | stacking state of a fuel cell. The side view of the separator which shows the surfaces to be laminated | stacked. Sectional drawing which shows each cross section of a fuel cell. Explanatory drawing of the cross-sectional state of a fuel cell. The characteristic view which shows the relationship between a reactive gas passage and a cell voltage. The disassembled perspective view of the fuel battery cell which shows 2nd Embodiment of this invention. The perspective view which similarly shows the lamination | stacking state of a fuel cell. The disassembled perspective view of the fuel battery cell which shows 2nd Embodiment of this invention. Explanatory drawing which shows the shape of the surface (A) and back surface (B) of the cathode separator used for the fuel cell of this embodiment. The perspective view which similarly shows the lamination | stacking state of a fuel cell. The side view of the separator which shows the surfaces to be laminated | stacked. Sectional drawing which shows each cross section of a fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell stack 2 Fuel cell 3 Current collector plate 4 Insulating layer 5 End plate 6 Tension plate 7 Membrane / electrode assembly, MEA
8, 9 Separator 8A, 9A Gas flow path 8B, 9B Refrigerant flow path 10A, 10B Porous material 11-13 Inlet manifold

Claims (4)

An electrolyte / electrode structure comprising an electrolyte membrane sandwiched between a pair of electrode catalyst layers;
It has a flat surface arranged in contact with at least one electrode catalyst layer of the electrolyte / electrode structure, and has an uneven groove shape on the other surface, and one reaction gas is supplied to one electrode catalyst layer. A conductive porous material to be supplied;
A conductive fluid shielding plate having a concave and convex groove shape contacting each other with the conductive porous body and laminated on the conductive porous body;
The concave portion formed on the opposite side of the contact surface with the conductive porous body due to the shape of the concave and convex grooves of the conductive fluid shielding plate, a part of the flow path of the cooling medium or the other reactive gas as the other electrode catalyst layer A fuel cell, characterized in that the fuel cell is a part of a flow path to be supplied to Provided with a flat surface arranged in contact with the other electrode catalyst layer of the electrolyte / electrode structure, the other surface has an uneven groove shape, and the other reaction gas is supplied to the other electrode catalyst layer. A second conductive porous body,
A second conductive fluid shielding plate that is laminated on the second conductive porous body with a concave and convex groove shape that contacts the second conductive porous body,
A cooling medium flow path is formed by recesses formed on the opposite side of the contact surface with the conductive porous body by the concave and convex groove shapes of the first and second conductive fluid shielding plates. The fuel cell according to claim 1. The electrolyte / electrode structure has a flat surface arranged in contact with the electrode catalyst layer of the oxidant electrode, and the other surface has a concave and convex groove shape, and oxidant gas is supplied to the electrode catalyst of the oxidant electrode. A conductive porous material to be supplied to the layer;
A first conductive fluid shielding plate that has a concave and convex groove shape that contacts the conductive porous body and is laminated on the conductive porous body;
An uneven groove shape for forming a flow path for supplying fuel gas to the electrode catalyst layer of the fuel electrode of the electrolyte / electrode structure is provided, and the uneven portion of the uneven groove shape is used as the electrode catalyst layer of the fuel electrode of the electrolyte / electrode structure. A second conductive fluid shielding plate disposed in contact with, and
2. The fuel cell according to claim 1, wherein a flow path for a cooling medium is formed by recesses formed on the back surface of the first and second conductive fluid shielding plates by the shape of the concave and convex grooves. Provided with a flat surface arranged in contact with the electrode catalyst layer of the fuel electrode of the electrolyte / electrode structure, and provided with an uneven groove shape on the other surface to supply fuel gas to the electrode catalyst layer of the fuel electrode A first conductive porous body,
A first conductive fluid shielding plate that is laminated on the first conductive porous body and has a concave and convex groove shape that contacts the first conductive porous body;
A flat surface arranged in contact with the electrode catalyst layer of the oxidant electrode of the electrolyte / electrode structure and a flat surface on the other side are provided, and an oxidant gas is supplied to the electrode catalyst layer of the oxidant electrode. A second conductive porous body;
A second conductive fluid shielding plate stacked on and in contact with the second conductive porous body,
The back surfaces of the first and second conductive fluid shielding plates are brought into contact with each other, and are formed on the opposite side of the contact surface with the first conductive porous body due to the concave and convex groove shape of the first conductive shielding plate. The fuel cell according to claim 1, wherein a flow path for the cooling medium is formed by the concave portion.

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